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NAME
curl - transfer a URL
SYNOPSIS
curl [options] [URL...]
DESCRIPTION
curl is a client to get documents/files from or send docu-
ments to a server, using any of the supported protocols
(HTTP, HTTPS, FTP, GOPHER, DICT, TELNET, LDAP or FILE).
The command is designed to work without user interaction
or any kind of interactivity.
curl offers a busload of useful tricks like proxy support,
user authentication, ftp upload, HTTP post, SSL (https:)
connections, cookies, file transfer resume and more.
URL
The URL syntax is protocol dependent. You'll find a
detailed description in RFC 2396.
You can specify multiple URLs or parts of URLs by writing
part sets within braces as in:
http://site.{one,two,three}.com
or you can get sequences of alphanumeric series by using
[] as in:
ftp://ftp.numericals.com/file[1-100].txt
ftp://ftp.numericals.com/file[001-100].txt (with lead-
ing zeros)
ftp://ftp.letters.com/file[a-z].txt
It is possible to specify up to 9 sets or series for a
URL, but no nesting is supported at the moment:
http://www.any.org/archive[1996-1999]/vol-
ume[1-4]part{a,b,c,index}.html
You can specify any amount of URLs on the command line.
They will be fetched in a sequential manner in the speci-
fied order.
Curl will attempt to re-use connections for multiple file
transfers, so that getting many files from the same server
will not do multiple connects / handshakes. This improves
speed. Of course this is only done on files specified on a
single command line and cannot be used between separate
curl invokes.
OPTIONS
-a/--append
(FTP) When used in a ftp upload, this will tell
curl to append to the target file instead of over-
writing it. If the file doesn't exist, it will be
created.
If this option is used twice, the second one will
disable append mode again.
-A/--user-agent <agent string>
(HTTP) Specify the User-Agent string to send to the
HTTP server. Some badly done CGIs fail if its not
set to "Mozilla/4.0". To encode blanks in the
string, surround the string with single quote
marks. This can also be set with the -H/--header
flag of course.
If this option is set more than once, the last one
will be the one that's used.
-b/--cookie <name=data>
(HTTP) Pass the data to the HTTP server as a
cookie. It is supposedly the data previously
received from the server in a "Set-Cookie:" line.
The data should be in the format "NAME1=VALUE1;
NAME2=VALUE2".
If no '=' letter is used in the line, it is treated
as a filename to use to read previously stored
cookie lines from, which should be used in this
session if they match. Using this method also acti-
vates the "cookie parser" which will make curl
record incoming cookies too, which may be handy if
you're using this in combination with the
-L/--location option. The file format of the file
to read cookies from should be plain HTTP headers
or the Netscape/Mozilla cookie file format.
NOTE that the file specified with -b/--cookie is
only used as input. No cookies will be stored in
the file. To store cookies, save the HTTP headers
to a file using -D/--dump-header!
If this option is set more than once, the last one
will be the one that's used.
-B/--use-ascii
Use ASCII transfer when getting an FTP file or LDAP
info. For FTP, this can also be enforced by using
an URL that ends with ";type=A". This option causes
data sent to stdout to be in text mode for win32
systems.
If this option is used twice, the second one will
disable ASCII usage.
--ciphers <list of ciphers>
(SSL) Specifies which ciphers to use in the connec-
tion. The list of ciphers must be using valid
ciphers. Read up on SSL cipher list details on this
URL: http://www.openssl.org/docs/apps/ciphers.html
(Option added in curl 7.9)
If this option is used several times, the last one
will override the others.
--connect-timeout <seconds>
Maximum time in seconds that you allow the connec-
tion to the server to take. This only limits the
connection phase, once curl has connected this
option is of no more use. See also the --max-time
option.
If this option is used several times, the last one
will be used.
-c/--cookie-jar <file name>
Specify to which file you want curl to write all
cookies after a completed operation. Curl writes
all cookies previously read from a specified file
as well as all cookies received from remote
server(s). If no cookies are known, no file will be
written. The file will be written using the
Netscape cookie file format. If you set the file
name to a single dash, "-", the cookies will be
written to stdout. (Option added in curl 7.9)
If this option is used several times, the last
specfied file name will be used.
-C/--continue-at <offset>
Continue/Resume a previous file transfer at the
given offset. The given offset is the exact number
of bytes that will be skipped counted from the
beginning of the source file before it is trans-
fered to the destination. If used with uploads,
the ftp server command SIZE will not be used by
curl.
Use "-C -" to tell curl to automatically find out
where/how to resume the transfer. It then uses the
given output/input files to figure that out.
If this option is used several times, the last one
will be used.
---create-dirs
When used in conjunction with the -o option, curl
will create the necessary local directory hierarchy
as needed.
--crlf (FTP) Convert LF to CRLF in upload. Useful for MVS
(OS/390).
If this option is used twice, the second will again
disable crlf converting.
-d/--data <data>
(HTTP) Sends the specified data in a POST request
to the HTTP server, in a way that can emulate as if
a user has filled in a HTML form and pressed the
submit button. Note that the data is sent exactly
as specified with no extra processing (with all
newlines cut off). The data is expected to be
"url-encoded". This will cause curl to pass the
data to the server using the content-type applica-
tion/x-www-form-urlencoded. Compare to -F. If more
than one -d/--data option is used on the same com-
mand line, the data pieces specified will be merged
together with a separating &-letter. Thus, using
'-d name=daniel -d skill=lousy' would generate a
post chunk that looks like
'name=daniel&skill=lousy'.
If you start the data with the letter @, the rest
should be a file name to read the data from, or -
if you want curl to read the data from stdin. The
contents of the file must already be url-encoded.
Multiple files can also be specified. Posting data
from a file named 'foobar' would thus be done with
"--data @foobar".
To post data purely binary, you should instead use
the --data-binary option.
-d/--data is the same as --data-ascii.
If this option is used several times, the ones fol-
lowing the first will append data.
--data-ascii <data>
(HTTP) This is an alias for the -d/--data option.
If this option is used several times, the ones fol-
lowing the first will append data.
--data-binary <data>
(HTTP) This posts data in a similar manner as
--data-ascii does, although when using this option
the entire context of the posted data is kept as-
is. If you want to post a binary file without the
strip-newlines feature of the --data-ascii option,
this is for you.
If this option is used several times, the ones
following the first will append data.
--disable-epsv
(FTP) Tell curl to disable the use of the EPSV com-
mand when doing passive FTP downloads. Curl will
normally always first attempt to use EPSV before
PASV, but with this option, it will not try using
EPSV.
If this option is used several times, each occur-
rence will toggle this on/off.
-D/--dump-header <file>
Write the protocol headers to the specified file.
This option is handy to use when you want to store
the cookies that a HTTP site sends to you. The
cookies could then be read in a second curl invoke
by using the -b/--cookie option!
When used on FTP, the ftp server response lines are
considered being "headers" and thus are saved
there.
If this option is used several times, the last one
will be used.
-e/--referer <URL>
(HTTP) Sends the "Referer Page" information to the
HTTP server. This can also be set with the
-H/--header flag of course. When used with
-L/--location you can append ";auto" to the referer
URL to make curl automatically set the previous URL
when it follows a Location: header. The ";auto"
string can be used alone, even if you don't set an
initial referer.
If this option is used several times, the last one
will be used.
--environment
(RISC OS ONLY) Sets a range of environment vari-
ables, using the names the -w option supports, to
easier allow extraction of useful information after
having run curl.
If this option is used several times, each occur-
rence will toggle this on/off.
--egd-file <file>
(HTTPS) Specify the path name to the Entropy Gath-
ering Daemon socket. The socket is used to seed the
random engine for SSL connections. See also the
--random-file option.
-E/--cert <certificate[:password]>
(HTTPS) Tells curl to use the specified certificate
file when getting a file with HTTPS. The certifi-
cate must be in PEM format. If the optional pass-
word isn't specified, it will be queried for on the
terminal. Note that this certificate is the private
key and the private certificate concatenated!
If this option is used several times, the last one
will be used.
--cacert <CA certificate>
(HTTPS) Tells curl to use the specified certificate
file to verify the peer. The file may contain mul-
tiple CA certificates. The certificate(s) must be
in PEM format.
curl recognizes the environment variable named
'CURL_CA_BUNDLE' if that is set, and uses the given
path as a path to a CA cert bundle. This option
overrides that variable.
The windows version of curl will automatically look
for a CA certs file named 'curl-ca-bundle.crt',
either in the same directory as curl.exe, or in the
Current Working Directory, or in any folder along
your PATH.
If this option is used several times, the last one
will be used.
--capath <CA certificate directory>
(HTTPS) Tells curl to use the specified certificate
directory to verify the peer. The certificates must
be in PEM format, and the directory must have been
processed using the c_rehash utility supplied with
openssl. Using --capath can allow curl to make
https connections much more efficiently than using
--cacert if the --cacert file contains many CA cer-
tificates.
If this option is used several times, the last one
will be used.
-f/--fail
(HTTP) Fail silently (no output at all) on server
errors. This is mostly done like this to better
enable scripts etc to better deal with failed
attempts. In normal cases when a HTTP server fails
to deliver a document, it returns a HTML document
stating so (which often also describes why and
more). This flag will prevent curl from outputting
that and fail silently instead.
If this option is used twice, the second will again
disable silent failure.
-F/--form <name=content>
(HTTP) This lets curl emulate a filled in form in
which a user has pressed the submit button. This
causes curl to POST data using the content-type
multipart/form-data according to RFC1867. This
enables uploading of binary files etc. To force the
'content' part to be be a file, prefix the file
name with an @ sign. To just get the content part
from a file, prefix the file name with the letter
<. The difference between @ and < is then that @
makes a file get attached in the post as a file
upload, while the < makes a text field and just get
the contents for that text field from a file.
Example, to send your password file to the server,
where 'password' is the name of the form-field to
which /etc/passwd will be the input:
curl -F password=@/etc/passwd www.mypasswords.com
To read the file's content from stdin insted of a
file, use - where the file name should've been.
This goes for both @ and < constructs.
This option can be used multiple times.
-g/--globoff
This option switches off the "URL globbing parser".
When you set this option, you can specify URLs that
contain the letters {}[] without having them being
interpreted by curl itself. Note that these letters
are not normal legal URL contents but they should
be encoded according to the URI standard.
-G/--get
When used, this option will make all data specified
with -d/--data or --data-binary to be used in a
HTTP GET request instead of the POST request that
otherwise would be used. The data will be appended
to the URL with a '?' separator. (Option added in
curl 7.9)
If used in combination with -I, the POST data will
instead be appended to the URL with a HEAD request.
If used multiple times, nothing special happens.
-h/--help
Usage help.
-H/--header <header>
(HTTP) Extra header to use when getting a web page.
You may specify any number of extra headers. Note
that if you should add a custom header that has the
same name as one of the internal ones curl would
use, your externally set header will be used
instead of the internal one. This allows you to
make even trickier stuff than curl would normally
do. You should not replace internally set headers
without knowing perfectly well what you're doing.
Replacing an internal header with one without con-
tent on the right side of the colon will prevent
that header from appearing.
This option can be used multiple times to
add/replace/remove multiple headers.
-i/--include
(HTTP) Include the HTTP-header in the output. The
HTTP-header includes things like server-name, date
of the document, HTTP-version and more...
If this option is used twice, the second will again
disable header include.
--interface <name>
Perform an operation using a specified interface.
You can enter interface name, IP address or host
name. An example could look like:
curl --interface eth0:1 http://www.netscape.com/
If this option is used several times, the last one
will be used.
-I/--head
(HTTP/FTP) Fetch the HTTP-header only! HTTP-servers
feature the command HEAD which this uses to get
nothing but the header of a document. When used on
a FTP file, curl displays the file size only.
If this option is used twice, the second will again
disable header only.
-j/--junk-session-cookies
(HTTP) When curl is told to read cookies from a
given file, this option will make it discard all
"session cookies". This will basicly have the same
effect as if a new session is started. Typical
browsers always discard session cookies when
they're closed down. (Added in 7.9.7)
If this option is used several times, each occur-
rence will toggle this on/off.
-k/--insecure
(SSL) This option explicitly allows curl to perform
"insecure" SSL connections and transfers. Starting
with curl 7.10, all SSL connections will be
attempted to be made secure by using the CA cer-
tificate bundle installed by default. This makes
all connections considered "insecure" to fail
unless -k/--insecure is used.
This option is ignored if --cacert or --capath is
used!
If this option is used twice, the second time will
again disable it.
--krb4 <level>
(FTP) Enable kerberos4 authentication and use. The
level must be entered and should be one of 'clear',
'safe', 'confidential' or 'private'. Should you use
a level that is not one of these, 'private' will
instead be used.
If this option is used several times, the last one
will be used.
-K/--config <config file>
Specify which config file to read curl arguments
from. The config file is a text file in which com-
mand line arguments can be written which then will
be used as if they were written on the actual com-
mand line. Options and their parameters must be
specified on the same config file line. If the
parameter is to contain white spaces, the parameter
must be inclosed within quotes. If the first col-
umn of a config line is a '#' character, the rest
of the line will be treated as a comment.
Specify the filename as '-' to make curl read the
file from stdin.
Note that to be able to specify a URL in the config
file, you need to specify it using the --url
option, and not by simply writing the URL on its
own line. So, it could look similar to this:
url = "http://curl.haxx.se/docs/"
This option can be used multiple times.
--limit-rate <speed>
Specify the maximum transfer rate you want curl to
use. This feature is useful if you have a limited
pipe and you'd like your transfer not use your
entire bandwidth.
The given speed is measured in bytes/second, unless
a suffix is appended. Appending 'k' or 'K' will
count the number as kilobytes, 'm' or M' makes it
megabytes while 'g' or 'G' makes it gigabytes.
Examples: 200K, 3m and 1G.
This option was introduced in curl 7.10.
If this option is used several times, the last one
will be used.
-l/--list-only
(FTP) When listing an FTP directory, this switch
forces a name-only view. Especially useful if you
want to machine-parse the contents of an FTP direc-
tory since the normal directory view doesn't use a
standard look or format.
This option causes an FTP NLST command to be sent.
Some FTP servers list only files in their response
to NLST; they do not include subdirectories and
symbolic links.
If this option is used twice, the second will again
disable list only.
-L/--location
(HTTP/HTTPS) If the server reports that the
requested page has a different location (indicated
with the header line Location:) this flag will let
curl attempt to reattempt the get on the new place.
If used together with -i or -I, headers from all
requested pages will be shown. If this flag is used
when making a HTTP POST, curl will automatically
switch to GET after the initial POST has been done.
If this option is used twice, the second will again
disable location following.
-m/--max-time <seconds>
Maximum time in seconds that you allow the whole
operation to take. This is useful for preventing
your batch jobs from hanging for hours due to slow
networks or links going down. This doesn't work
fully in win32 systems. See also the --connect-
timeout option.
If this option is used several times, the last one
will be used.
-M/--manual
Manual. Display the huge help text.
-n/--netrc
Makes curl scan the .netrc file in the user's home
directory for login name and password. This is typ-
ically used for ftp on unix. If used with http,
curl will enable user authentication. See netrc(4)
or ftp(1) for details on the file format. Curl will
not complain if that file hasn't the right permis-
sions (it should not be world nor group readable).
The environment variable "HOME" is used to find the
home directory.
A quick and very simple example of how to setup a
.netrc to allow curl to ftp to the machine
host.domain.com with user name 'myself' and pass-
word 'secret' should look similar to:
machine host.domain.com login myself password
secret
If this option is used twice, the second will again
disable netrc usage.
-N/--no-buffer
Disables the buffering of the output stream. In
normal work situations, curl will use a standard
buffered output stream that will have the effect
that it will output the data in chunks, not neces-
sarily exactly when the data arrives. Using this
option will disable that buffering.
If this option is used twice, the second will again
switch on buffering.
-o/--output <file>
Write output to <file> instead of stdout. If you
are using {} or [] to fetch multiple documents, you
can use '#' followed by a number in the <file>
specifier. That variable will be replaced with the
current string for the URL being fetched. Like in:
curl http://{one,two}.site.com -o "file_#1.txt"
or use several variables like:
curl http://{site,host}.host[1-5].com -o "#1_#2"
You may use this option as many times as you have
number of URLs.
See also the --create-dirs option to create the
local directories dynamically.
-O/--remote-name
Write output to a local file named like the remote
file we get. (Only the file part of the remote file
is used, the path is cut off.)
You may use this option as many times as you have
number of URLs.
-p/--proxytunnel
When an HTTP proxy is used, this option will cause
non-HTTP protocols to attempt to tunnel through the
proxy instead of merely using it to do HTTP-like
operations. The tunnel approach is made with the
HTTP proxy CONNECT request and requires that the
proxy allows direct connect to the remote port num-
ber curl wants to tunnel through to.
If this option is used twice, the second will again
disable proxy tunnel.
-P/--ftpport <address>
(FTP) Reverses the initiator/listener roles when
connecting with ftp. This switch makes Curl use the
PORT command instead of PASV. In practice, PORT
tells the server to connect to the client's speci-
fied address and port, while PASV asks the server
for an ip address and port to connect to. <address>
should be one of:
interface i.e "eth0" to specify which interface's
IP address you want to use (Unix only)
IP address i.e "192.168.10.1" to specify exact IP
number
host name i.e "my.host.domain" to specify machine
- (any single-letter string) to make it
pick the machine's default
If this option is used several times, the last one will be
used.
-q If used as the first parameter on the command line,
the $HOME/.curlrc file will not be read and used as
a config file.
-Q/--quote <comand>
(FTP) Send an arbitrary command to the remote FTP
server, by using the QUOTE command of the server.
Not all servers support this command, and the set
of QUOTE commands are server specific! Quote com-
mands are sent BEFORE the transfer is taking place.
To make commands take place after a successful
transfer, prefix them with a dash '-'. You may
specify any amount of commands to be run before and
after the transfer. If the server returns failure
for one of the commands, the entire operation will
be aborted.
This option can be used multiple times.
--random-file <file>
(HTTPS) Specify the path name to file containing
what will be considered as random data. The data is
used to seed the random engine for SSL connections.
See also the --edg-file option.
-r/--range <range>
(HTTP/FTP) Retrieve a byte range (i.e a partial
document) from a HTTP/1.1 or FTP server. Ranges can
be specified in a number of ways.
0-499 specifies the first 500 bytes
500-999 specifies the second 500 bytes
-500 specifies the last 500 bytes
9500 specifies the bytes from offset 9500 and
forward
0-0,-1 specifies the first and last byte
only(*)(H)
500-700,600-799
specifies 300 bytes from offset 500(H)
100-199,500-599
specifies two separate 100 bytes
ranges(*)(H)
(*) = NOTE that this will cause the server to reply with a
multipart response!
You should also be aware that many HTTP/1.1 servers do not
have this feature enabled, so that when you attempt to get
a range, you'll instead get the whole document.
FTP range downloads only support the simple syntax 'start-
stop' (optionally with one of the numbers omitted). It
depends on the non-RFC command SIZE.
If this option is used several times, the last one will be
used.
-R/--remote-time
When used, this will make libcurl attempt to figure
out the timestamp of the remote file, and if that
is available make the local file get that same
timestamp.
If this option is used twice, the second time dis-
ables this again.
-s/--silent
Silent mode. Don't show progress meter or error
messages. Makes Curl mute.
If this option is used twice, the second will again
disable mute.
-S/--show-error
When used with -s it makes curl show error message
if it fails.
If this option is used twice, the second will again
disable show error.
--stderr <file>
Redirect all writes to stderr to the specified file
instead. If the file name is a plain '-', it is
instead written to stdout. This option has no point
when you're using a shell with decent redirecting
capabilities.
If this option is used several times, the last one
will be used.
-t/--telnet-option <OPT=val>
Pass options to the telnet protocol. Supported
options are:
TTYPE=<term> Sets the terminal type.
XDISPLOC=<X display> Sets the X display location.
NEW_ENV=<var,val> Sets an environment variable.
-T/--upload-file <file>
This transfers the specified local file to the
remote URL. If there is no file part in the speci-
fied URL, Curl will append the local file name.
NOTE that you must use a trailing / on the last
directory to really prove to Curl that there is no
file name or curl will think that your last direc-
tory name is the remote file name to use. That will
most likely cause the upload operation to fail. If
this is used on a http(s) server, the PUT command
will be used.
Use the file name "-" (a single dash) to use stdin
instead of a given file.
If this option is used several times, the last one
will be used.
--trace <file>
Enables a full trace dump of all incoming and out-
going data, including descriptive information, to
the given output file. Use "-" as filename to have
the output sent to stdout.
If this option is used several times, the last one
will be used. (Added in curl 7.9.7)
--trace-ascii <file>
Enables a full trace dump of all incoming and out-
going data, including descriptive information, to
the given output file. Use "-" as filename to have
the output sent to stdout.
This is very similar to --trace, but leaves out the
hex part and only shows the ASCII part of the dump.
It makes smaller output that might be easier to
read for untrained humans.
If this option is used several times, the last one
will be used. (Added in curl 7.9.7)
-u/--user <user:password>
Specify user and password to use when fetching.
Read the MANUAL for detailed examples of how to use
this. If no password is specified, curl will ask
for it interactively.
If this option is used several times, the last one
will be used.
-U/--proxy-user <user:password>
Specify user and password to use for Proxy authen-
tication. If no password is specified, curl will
ask for it interactively.
If this option is used several times, the last one
will be used.
--url <URL>
Specify a URL to fetch. This option is mostly handy
when you want to specify URL(s) in a config file.
This option may be used any number of times. To
control where this URL is written, use the -o or
the -O options.
-v/--verbose
Makes the fetching more verbose/talkative. Mostly
usable for debugging. Lines starting with '>' means
data sent by curl, '<' means data received by curl
that is hidden in normal cases and lines starting
with '*' means additional info provided by curl.
Note that if you want to see HTTP headers in the
output, -i/--include might be option you're looking
for.
If you think this option still doesn't give you
enough details, consider using --trace or --trace-
ascii instead.
If this option is used twice, the second will again
disable verbose.
-V/--version
Displays the full version of curl, libcurl and
other 3rd party libraries linked with the exe-
cutable.
-w/--write-out <format>
Defines what to display after a completed and suc-
cessful operation. The format is a string that may
contain plain text mixed with any number of vari-
ables. The string can be specified as "string", to
get read from a particular file you specify it
"@filename" and to tell curl to read the format
from stdin you write "@-".
The variables present in the output format will be
substituted by the value or text that curl thinks
fit, as described below. All variables are speci-
fied like %{variable_name} and to output a normal %
you just write them like %%. You can output a new-
line by using \n, a carriage return with \r and a
tab space with \t.
NOTE: The %-letter is a special letter in the
win32-environment, where all occurrences of % must
be doubled when using this option.
Available variables are at this point:
url_effective The URL that was fetched last. This
is mostly meaningful if you've told
curl to follow location: headers.
http_code The numerical code that was found in
the last retrieved HTTP(S) page.
time_total The total time, in seconds, that the
full operation lasted. The time will
be displayed with millisecond reso-
lution.
time_namelookup
The time, in seconds, it took from
the start until the name resolving
was completed.
time_connect The time, in seconds, it took from
the start until the connect to the
remote host (or proxy) was com-
pleted.
time_pretransfer
The time, in seconds, it took from
the start until the file transfer is
just about to begin. This includes
all pre-transfer commands and nego-
tiations that are specific to the
particular protocol(s) involved.
time_starttransfer
The time, in seconds, it took from
the start until the first byte is
just about to be transfered. This
includes time_pretransfer and also
the time the server needs to calcu-
late the result.
size_download The total amount of bytes that were
downloaded.
size_upload The total amount of bytes that were
uploaded.
size_header The total amount of bytes of the
downloaded headers.
size_request The total amount of bytes that were
sent in the HTTP request.
speed_download The average download speed that curl
measured for the complete download.
speed_upload The average upload speed that curl
measured for the complete upload.
content_type The Content-Type of the requested
document, if there was any. (Added
in 7.9.5)
If this option is used several times, the last one will be
used.
-x/--proxy <proxyhost[:port]>
Use specified HTTP proxy. If the port number is not
specified, it is assumed at port 1080.
This option overrides existing environment vari-
ables that sets proxy to use. If there's an envi-
ronment variable setting a proxy, you can set proxy
to "" to override it.
Note that all operations that are performed over a
HTTP proxy will transparantly be converted to HTTP.
It means that certain protocol specific operations
might not be available. This is not the case if you
can tunnel through the proxy, as done with the
-p/--proxytunnel option.
If this option is used several times, the last one
will be used.
-X/--request <command>
(HTTP) Specifies a custom request to use when com-
municating with the HTTP server. The specified
request will be used instead of the standard GET.
Read the HTTP 1.1 specification for details and
explanations.
(FTP) Specifies a custom FTP command to use instead
of LIST when doing file lists with ftp.
If this option is used several times, the last one
will be used.
-y/--speed-time <time>
If a download is slower than speed-limit bytes per
second during a speed-time period, the download
gets aborted. If speed-time is used, the default
speed-limit will be 1 unless set with -y.
This option controls transfers and thus will not
affect slow connects etc. If this is a concern for
you, try the --connect-timeout option.
If this option is used several times, the last one
will be used.
-Y/--speed-limit <speed>
If a download is slower than this given speed, in
bytes per second, for speed-time seconds it gets
aborted. speed-time is set with -Y and is 30 if not
set.
If this option is used several times, the last one
will be used.
-z/--time-cond <date expression>
(HTTP) Request to get a file that has been modified
later than the given time and date, or one that has
been modified before that time. The date expression
can be all sorts of date strings or if it doesn't
match any internal ones, it tries to get the time
from a given file name instead! See the GNU date(1)
or curl_getdate(3) man pages for date expression
details.
Start the date expression with a dash (-) to make
it request for a document that is older than the
given date/time, default is a document that is
newer than the specified date/time.
If this option is used several times, the last one
will be used.
-Z/--max-redirs <num>
Set maximum number of redirection-followings
allowed. If -L/--location is used, this option can
be used to prevent curl from following redirections
"in absurdum".
If this option is used several times, the last one
will be used.
-3/--sslv3
(HTTPS) Forces curl to use SSL version 3 when nego-
tiating with a remote SSL server.
-2/--sslv2
(HTTPS) Forces curl to use SSL version 2 when nego-
tiating with a remote SSL server.
-0/--http1.0
(HTTP) Forces curl to issue its requests using HTTP
1.0 instead of using its internally preferred: HTTP
1.1.
-#/--progress-bar
Make curl display progress information as a
progress bar instead of the default statistics.
If this option is used twice, the second will again
disable the progress bar.
FILES
~/.curlrc
Default config file.
ENVIRONMENT
http_proxy [protocol://]<host>[:port]
Sets proxy server to use for HTTP.
HTTPS_PROXY [protocol://]<host>[:port]
Sets proxy server to use for HTTPS.
FTP_PROXY [protocol://]<host>[:port]
Sets proxy server to use for FTP.
GOPHER_PROXY [protocol://]<host>[:port]
Sets proxy server to use for GOPHER.
ALL_PROXY [protocol://]<host>[:port]
Sets proxy server to use if no protocol-specific
proxy is set.
NO_PROXY <comma-separated list of hosts>
list of host names that shouldn't go through any
proxy. If set to a asterisk
EXIT CODES
There exists a bunch of different error codes and their
corresponding error messages that may appear during bad
conditions. At the time of this writing, the exit codes
are:
1 Unsupported protocol. This build of curl has no
support for this protocol.
2 Failed to initialize.
3 URL malformat. The syntax was not correct.
4 URL user malformatted. The user-part of the URL
syntax was not correct.
5 Couldn't resolve proxy. The given proxy host could
not be resolved.
6 Couldn't resolve host. The given remote host was
not resolved.
7 Failed to connect to host.
8 FTP weird server reply. The server sent data curl
couldn't parse.
9 FTP access denied. The server denied login.
10 FTP user/password incorrect. Either one or both
were not accepted by the server.
11 FTP weird PASS reply. Curl couldn't parse the reply
sent to the PASS request.
12 FTP weird USER reply. Curl couldn't parse the reply
sent to the USER request.
13 FTP weird PASV reply, Curl couldn't parse the reply
sent to the PASV request.
14 FTP weird 227 format. Curl couldn't parse the
227-line the server sent.
15 FTP can't get host. Couldn't resolve the host IP we
got in the 227-line.
16 FTP can't reconnect. Couldn't connect to the host
we got in the 227-line.
17 FTP couldn't set binary. Couldn't change transfer
method to binary.
18 Partial file. Only a part of the file was trans-
fered.
19 FTP couldn't download/access the given file, the
RETR (or similar) command failed.
20 FTP write error. The transfer was reported bad by
the server.
21 FTP quote error. A quote command returned error
from the server.
22 HTTP page not retrieved. The requested url was not
found or returned another error with the HTTP error
code being 400 or above. This return code only
appears if --fail is used.
23 Write error. Curl couldn't write data to a local
filesystem or similar.
24 Malformat user. User name badly specified.
25 FTP couldn't STOR file. The server denied the STOR
operation.
26 Read error. Various reading problems.
27 Out of memory. A memory allocation request failed.
28 Operation timeout. The specified time-out period
was reached according to the conditions.
29 FTP couldn't set ASCII. The server returned an
unknown reply.
30 FTP PORT failed. The PORT command failed.
31 FTP couldn't use REST. The REST command failed.
32 FTP couldn't use SIZE. The SIZE command failed. The
command is an extension to the original FTP spec
RFC 959.
33 HTTP range error. The range "command" didn't work.
34 HTTP post error. Internal post-request generation
error.
35 SSL connect error. The SSL handshaking failed.
36 FTP bad download resume. Couldn't continue an ear-
lier aborted download.
37 FILE couldn't read file. Failed to open the file.
Permissions?
38 LDAP cannot bind. LDAP bind operation failed.
39 LDAP search failed.
40 Library not found. The LDAP library was not found.
41 Function not found. A required LDAP function was
not found.
42 Aborted by callback. An application told curl to
abort the operation.
43 Internal error. A function was called with a bad
parameter.
44 Internal error. A function was called in a bad
order.
45 Interface error. A specified outgoing interface
could not be used.
46 Bad password entered. An error was signaled when
the password was entered.
47 Too many redirects. When following redirects, curl
hit the maximum amount.
48 Unknown TELNET option specified.
49 Malformed telnet option.
51 The remote peer's SSL certificate wasn't ok
52 The server didn't reply anything, which here is
considered an error.
53 SSL crypto engine not found
54 Cannot set SSL crypto engine as default
55 Failed sending network data
56 Failure in receiving network data
57 Share is in use (internal error)
58 Problem with the local certificate
59 Couldn't use specified SSL cipher
60 Problem with the CA cert (path? permission?)
61 Unrecognized transfer encoding
XX There will appear more error codes here in future
releases. The existing ones are meant to never
change.
BUGS
If you do find bugs, mail them to curl-bug@haxx.se.
AUTHORS / CONTRIBUTORS
Daniel Stenberg is the main author, but the whole list of
contributors is found in the separate THANKS file.
WWW
http://curl.haxx.se
FTP
ftp://ftp.sunet.se/pub/www/utilities/curl/
SEE ALSO
ftp(1), wget(1), snarf(1)
LATEST VERSION
You always find news about what's going on as well as the latest versions
from the curl web pages, located at:
http://curl.haxx.se
SIMPLE USAGE
Get the main page from netscape's web-server:
curl http://www.netscape.com/
Get the root README file from funet's ftp-server:
curl ftp://ftp.funet.fi/README
Get a web page from a server using port 8000:
curl http://www.weirdserver.com:8000/
Get a list of the root directory of an FTP site:
curl ftp://cool.haxx.se/
Get a gopher document from funet's gopher server:
curl gopher://gopher.funet.fi
Get the definition of curl from a dictionary:
curl dict://dict.org/m:curl
Fetch two documents at once:
curl ftp://cool.haxx.se/ http://www.weirdserver.com:8000/
DOWNLOAD TO A FILE
Get a web page and store in a local file:
curl -o thatpage.html http://www.netscape.com/
Get a web page and store in a local file, make the local file get the name
of the remote document (if no file name part is specified in the URL, this
will fail):
curl -O http://www.netscape.com/index.html
Fetch two files and store them with their remote names:
curl -O www.haxx.se/index.html -O curl.haxx.se/download.html
USING PASSWORDS
FTP
To ftp files using name+passwd, include them in the URL like:
curl ftp://name:passwd@machine.domain:port/full/path/to/file
or specify them with the -u flag like
curl -u name:passwd ftp://machine.domain:port/full/path/to/file
HTTP
The HTTP URL doesn't support user and password in the URL string. Curl
does support that anyway to provide a ftp-style interface and thus you can
pick a file like:
curl http://name:passwd@machine.domain/full/path/to/file
or specify user and password separately like in
curl -u name:passwd http://machine.domain/full/path/to/file
NOTE! Since HTTP URLs don't support user and password, you can't use that
style when using Curl via a proxy. You _must_ use the -u style fetch
during such circumstances.
HTTPS
Probably most commonly used with private certificates, as explained below.
GOPHER
Curl features no password support for gopher.
PROXY
Get an ftp file using a proxy named my-proxy that uses port 888:
curl -x my-proxy:888 ftp://ftp.leachsite.com/README
Get a file from a HTTP server that requires user and password, using the
same proxy as above:
curl -u user:passwd -x my-proxy:888 http://www.get.this/
Some proxies require special authentication. Specify by using -U as above:
curl -U user:passwd -x my-proxy:888 http://www.get.this/
See also the environment variables Curl support that offer further proxy
control.
RANGES
With HTTP 1.1 byte-ranges were introduced. Using this, a client can request
to get only one or more subparts of a specified document. Curl supports
this with the -r flag.
Get the first 100 bytes of a document:
curl -r 0-99 http://www.get.this/
Get the last 500 bytes of a document:
curl -r -500 http://www.get.this/
Curl also supports simple ranges for FTP files as well. Then you can only
specify start and stop position.
Get the first 100 bytes of a document using FTP:
curl -r 0-99 ftp://www.get.this/README
UPLOADING
FTP
Upload all data on stdin to a specified ftp site:
curl -T - ftp://ftp.upload.com/myfile
Upload data from a specified file, login with user and password:
curl -T uploadfile -u user:passwd ftp://ftp.upload.com/myfile
Upload a local file to the remote site, and use the local file name remote
too:
curl -T uploadfile -u user:passwd ftp://ftp.upload.com/
Upload a local file to get appended to the remote file using ftp:
curl -T localfile -a ftp://ftp.upload.com/remotefile
Curl also supports ftp upload through a proxy, but only if the proxy is
configured to allow that kind of tunneling. If it does, you can run curl in
a fashion similar to:
curl --proxytunnel -x proxy:port -T localfile ftp.upload.com
HTTP
Upload all data on stdin to a specified http site:
curl -T - http://www.upload.com/myfile
Note that the http server must've been configured to accept PUT before this
can be done successfully.
For other ways to do http data upload, see the POST section below.
VERBOSE / DEBUG
If curl fails where it isn't supposed to, if the servers don't let you in,
if you can't understand the responses: use the -v flag to get verbose
fetching. Curl will output lots of info and what it sends and receives in
order to let the user see all client-server interaction (but it won't show
you the actual data).
curl -v ftp://ftp.upload.com/
To get even more details and information on what curl does, try using the
--trace or --trace-ascii options with a given file name to log to, like
this:
curl --trace trace.txt www.haxx.se
DETAILED INFORMATION
Different protocols provide different ways of getting detailed information
about specific files/documents. To get curl to show detailed information
about a single file, you should use -I/--head option. It displays all
available info on a single file for HTTP and FTP. The HTTP information is a
lot more extensive.
For HTTP, you can get the header information (the same as -I would show)
shown before the data by using -i/--include. Curl understands the
-D/--dump-header option when getting files from both FTP and HTTP, and it
will then store the headers in the specified file.
Store the HTTP headers in a separate file (headers.txt in the example):
curl --dump-header headers.txt curl.haxx.se
Note that headers stored in a separate file can be very useful at a later
time if you want curl to use cookies sent by the server. More about that in
the cookies section.
POST (HTTP)
It's easy to post data using curl. This is done using the -d <data>
option. The post data must be urlencoded.
Post a simple "name" and "phone" guestbook.
curl -d "name=Rafael%20Sagula&phone=3320780" \
http://www.where.com/guest.cgi
How to post a form with curl, lesson #1:
Dig out all the <input> tags in the form that you want to fill in. (There's
a perl program called formfind.pl on the curl site that helps with this).
If there's a "normal" post, you use -d to post. -d takes a full "post
string", which is in the format
<variable1>=<data1>&<variable2>=<data2>&...
The 'variable' names are the names set with "name=" in the <input> tags, and
the data is the contents you want to fill in for the inputs. The data *must*
be properly URL encoded. That means you replace space with + and that you
write weird letters with %XX where XX is the hexadecimal representation of
the letter's ASCII code.
Example:
(page located at http://www.formpost.com/getthis/
<form action="post.cgi" method="post">
<input name=user size=10>
<input name=pass type=password size=10>
<input name=id type=hidden value="blablabla">
<input name=ding value="submit">
</form>
We want to enter user 'foobar' with password '12345'.
To post to this, you enter a curl command line like:
curl -d "user=foobar&pass=12345&id=blablabla&dig=submit" (continues)
http://www.formpost.com/getthis/post.cgi
While -d uses the application/x-www-form-urlencoded mime-type, generally
understood by CGI's and similar, curl also supports the more capable
multipart/form-data type. This latter type supports things like file upload.
-F accepts parameters like -F "name=contents". If you want the contents to
be read from a file, use <@filename> as contents. When specifying a file,
you can also specify the file content type by appending ';type=<mime type>'
to the file name. You can also post the contents of several files in one
field. For example, the field name 'coolfiles' is used to send three files,
with different content types using the following syntax:
curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \
http://www.post.com/postit.cgi
If the content-type is not specified, curl will try to guess from the file
extension (it only knows a few), or use the previously specified type (from
an earlier file if several files are specified in a list) or else it will
using the default type 'text/plain'.
Emulate a fill-in form with -F. Let's say you fill in three fields in a
form. One field is a file name which to post, one field is your name and one
field is a file description. We want to post the file we have written named
"cooltext.txt". To let curl do the posting of this data instead of your
favourite browser, you have to read the HTML source of the form page and
find the names of the input fields. In our example, the input field names
are 'file', 'yourname' and 'filedescription'.
curl -F "file=@cooltext.txt" -F "yourname=Daniel" \
-F "filedescription=Cool text file with cool text inside" \
http://www.post.com/postit.cgi
To send two files in one post you can do it in two ways:
1. Send multiple files in a single "field" with a single field name:
curl -F "pictures=@dog.gif,cat.gif"
2. Send two fields with two field names:
curl -F "docpicture=@dog.gif" -F "catpicture=@cat.gif"
REFERRER
A HTTP request has the option to include information about which address
that referred to actual page. Curl allows you to specify the
referrer to be used on the command line. It is especially useful to
fool or trick stupid servers or CGI scripts that rely on that information
being available or contain certain data.
curl -e www.coolsite.com http://www.showme.com/
NOTE: The referer field is defined in the HTTP spec to be a full URL.
USER AGENT
A HTTP request has the option to include information about the browser
that generated the request. Curl allows it to be specified on the command
line. It is especially useful to fool or trick stupid servers or CGI
scripts that only accept certain browsers.
Example:
curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/
Other common strings:
'Mozilla/3.0 (Win95; I)' Netscape Version 3 for Windows 95
'Mozilla/3.04 (Win95; U)' Netscape Version 3 for Windows 95
'Mozilla/2.02 (OS/2; U)' Netscape Version 2 for OS/2
'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)' NS for AIX
'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)' NS for Linux
Note that Internet Explorer tries hard to be compatible in every way:
'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)' MSIE for W95
Mozilla is not the only possible User-Agent name:
'Konqueror/1.0' KDE File Manager desktop client
'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser
COOKIES
Cookies are generally used by web servers to keep state information at the
client's side. The server sets cookies by sending a response line in the
headers that looks like 'Set-Cookie: <data>' where the data part then
typically contains a set of NAME=VALUE pairs (separated by semicolons ';'
like "NAME1=VALUE1; NAME2=VALUE2;"). The server can also specify for what
path the "cookie" should be used for (by specifying "path=value"), when the
cookie should expire ("expire=DATE"), for what domain to use it
("domain=NAME") and if it should be used on secure connections only
("secure").
If you've received a page from a server that contains a header like:
Set-Cookie: sessionid=boo123; path="/foo";
it means the server wants that first pair passed on when we get anything in
a path beginning with "/foo".
Example, get a page that wants my name passed in a cookie:
curl -b "name=Daniel" www.sillypage.com
Curl also has the ability to use previously received cookies in following
sessions. If you get cookies from a server and store them in a file in a
manner similar to:
curl --dump-header headers www.example.com
... you can then in a second connect to that (or another) site, use the
cookies from the 'headers' file like:
curl -b headers www.example.com
While saving headers to a file is a working way to store cookies, it is
however error-prone and not the prefered way to do this. Instead, make curl
save the incoming cookies using the well-known netscape cookie format like
this:
curl -c cookies.txt www.example.com
Note that by specifying -b you enable the "cookie awareness" and with -L
you can make curl follow a location: (which often is used in combination
with cookies). So that if a site sends cookies and a location, you can
use a non-existing file to trigger the cookie awareness like:
curl -L -b empty.txt www.example.com
The file to read cookies from must be formatted using plain HTTP headers OR
as netscape's cookie file. Curl will determine what kind it is based on the
file contents. In the above command, curl will parse the header and store
the cookies received from www.example.com. curl will send to the server the
stored cookies which match the request as it follows the location. The
file "empty.txt" may be a non-existant file.
Alas, to both read and write cookies from a netscape cookie file, you can
set both -b and -c to use the same file:
curl -b cookies.txt -c cookies.txt www.example.com
PROGRESS METER
The progress meter exists to show a user that something actually is
happening. The different fields in the output have the following meaning:
% Total % Received % Xferd Average Speed Time Curr.
Dload Upload Total Current Left Speed
0 151M 0 38608 0 0 9406 0 4:41:43 0:00:04 4:41:39 9287
From left-to-right:
% - percentage completed of the whole transfer
Total - total size of the whole expected transfer
% - percentage completed of the download
Received - currently downloaded amount of bytes
% - percentage completed of the upload
Xferd - currently uploaded amount of bytes
Average Speed
Dload - the average transfer speed of the download
Average Speed
Upload - the average transfer speed of the upload
Time Total - expected time to complete the operation
Time Current - time passed since the invoke
Time Left - expected time left to completetion
Curr.Speed - the average transfer speed the last 5 seconds (the first
5 seconds of a transfer is based on less time of course.)
The -# option will display a totally different progress bar that doesn't
need much explanation!
SPEED LIMIT
Curl allows the user to set the transfer speed conditions that must be met
to let the transfer keep going. By using the switch -y and -Y you
can make curl abort transfers if the transfer speed is below the specified
lowest limit for a specified time.
To have curl abort the download if the speed is slower than 3000 bytes per
second for 1 minute, run:
curl -Y 3000 -y 60 www.far-away-site.com
This can very well be used in combination with the overall time limit, so
that the above operatioin must be completed in whole within 30 minutes:
curl -m 1800 -Y 3000 -y 60 www.far-away-site.com
Forcing curl not to transfer data faster than a given rate is also possible,
which might be useful if you're using a limited bandwidth connection and you
don't want your transfer to use all of it (sometimes referred to as
"bandwith throttle").
Make curl transfer data no faster than 10 kilobytes per second:
curl --limit-rate 10K www.far-away-site.com
or
curl --limit-rate 10240 www.far-away-site.com
Or prevent curl from uploading data faster than 1 megabyte per second:
curl -T upload --limit-rate 1M ftp://uploadshereplease.com
When using the --limit-rate option, the transfer rate is regulated on a
per-second basis, which will cause the total transfer speed to become lower
than the given number. Sometimes of course substantially lower, if your
transfer stalls during periods.
CONFIG FILE
Curl automatically tries to read the .curlrc file (or _curlrc file on win32
systems) from the user's home dir on startup.
The config file could be made up with normal command line switches, but you
can also specify the long options without the dashes to make it more
readable. You can separate the options and the parameter with spaces, or
with = or :. Comments can be used within the file. If the first letter on a
line is a '#'-letter the rest of the line is treated as a comment.
If you want the parameter to contain spaces, you must inclose the entire
parameter within double quotes ("). Within those quotes, you specify a
quote as \".
NOTE: You must specify options and their arguments on the same line.
Example, set default time out and proxy in a config file:
# We want a 30 minute timeout:
-m 1800
# ... and we use a proxy for all accesses:
proxy = proxy.our.domain.com:8080
White spaces ARE significant at the end of lines, but all white spaces
leading up to the first characters of each line are ignored.
Prevent curl from reading the default file by using -q as the first command
line parameter, like:
curl -q www.thatsite.com
Force curl to get and display a local help page in case it is invoked
without URL by making a config file similar to:
# default url to get
url = "http://help.with.curl.com/curlhelp.html"
You can specify another config file to be read by using the -K/--config
flag. If you set config file name to "-" it'll read the config from stdin,
which can be handy if you want to hide options from being visible in process
tables etc:
echo "user = user:passwd" | curl -K - http://that.secret.site.com
EXTRA HEADERS
When using curl in your own very special programs, you may end up needing
to pass on your own custom headers when getting a web page. You can do
this by using the -H flag.
Example, send the header "X-you-and-me: yes" to the server when getting a
page:
curl -H "X-you-and-me: yes" www.love.com
This can also be useful in case you want curl to send a different text in a
header than it normally does. The -H header you specify then replaces the
header curl would normally send. If you replace an internal header with an
empty one, you prevent that header from being sent. To prevent the Host:
header from being used:
curl -H "Host:" www.server.com
FTP and PATH NAMES
Do note that when getting files with the ftp:// URL, the given path is
relative the directory you enter. To get the file 'README' from your home
directory at your ftp site, do:
curl ftp://user:passwd@my.site.com/README
But if you want the README file from the root directory of that very same
site, you need to specify the absolute file name:
curl ftp://user:passwd@my.site.com//README
(I.e with an extra slash in front of the file name.)
FTP and firewalls
The FTP protocol requires one of the involved parties to open a second
connction as soon as data is about to get transfered. There are two ways to
do this.
The default way for curl is to issue the PASV command which causes the
server to open another port and await another connection performed by the
client. This is good if the client is behind a firewall that don't allow
incoming connections.
curl ftp.download.com
If the server for example, is behind a firewall that don't allow connections
on other ports than 21 (or if it just doesn't support the PASV command), the
other way to do it is to use the PORT command and instruct the server to
connect to the client on the given (as parameters to the PORT command) IP
number and port.
The -P flag to curl supports a few different options. Your machine may have
several IP-addresses and/or network interfaces and curl allows you to select
which of them to use. Default address can also be used:
curl -P - ftp.download.com
Download with PORT but use the IP address of our 'le0' interface (this does
not work on windows):
curl -P le0 ftp.download.com
Download with PORT but use 192.168.0.10 as our IP address to use:
curl -P 192.168.0.10 ftp.download.com
NETWORK INTERFACE
Get a web page from a server using a specified port for the interface:
curl --interface eth0:1 http://www.netscape.com/
or
curl --interface 192.168.1.10 http://www.netscape.com/
HTTPS
Secure HTTP requires SSL libraries to be installed and used when curl is
built. If that is done, curl is capable of retrieving and posting documents
using the HTTPS procotol.
Example:
curl https://www.secure-site.com
Curl is also capable of using your personal certificates to get/post files
from sites that require valid certificates. The only drawback is that the
certificate needs to be in PEM-format. PEM is a standard and open format to
store certificates with, but it is not used by the most commonly used
browsers (Netscape and MSIE both use the so called PKCS#12 format). If you
want curl to use the certificates you use with your (favourite) browser, you
may need to download/compile a converter that can convert your browser's
formatted certificates to PEM formatted ones. This kind of converter is
included in recent versions of OpenSSL, and for older versions Dr Stephen
N. Henson has written a patch for SSLeay that adds this functionality. You
can get his patch (that requires an SSLeay installation) from his site at:
http://www.drh-consultancy.demon.co.uk/
Example on how to automatically retrieve a document using a certificate with
a personal password:
curl -E /path/to/cert.pem:password https://secure.site.com/
If you neglect to specify the password on the command line, you will be
prompted for the correct password before any data can be received.
Many older SSL-servers have problems with SSLv3 or TLS, that newer versions
of OpenSSL etc is using, therefore it is sometimes useful to specify what
SSL-version curl should use. Use -3, -2 or -1 to specify that exact SSL
version to use (for SSLv3, SSLv2 or TLSv1 respectively):
curl -2 https://secure.site.com/
Otherwise, curl will first attempt to use v3 and then v2.
To use OpenSSL to convert your favourite browser's certificate into a PEM
formatted one that curl can use, do something like this (assuming netscape,
but IE is likely to work similarly):
You start with hitting the 'security' menu button in netscape.
Select 'certificates->yours' and then pick a certificate in the list
Press the 'export' button
enter your PIN code for the certs
select a proper place to save it
Run the 'openssl' application to convert the certificate. If you cd to the
openssl installation, you can do it like:
# ./apps/openssl pkcs12 -in [file you saved] -clcerts -out [PEMfile]
RESUMING FILE TRANSFERS
To continue a file transfer where it was previously aborted, curl supports
resume on http(s) downloads as well as ftp uploads and downloads.
Continue downloading a document:
curl -C - -o file ftp://ftp.server.com/path/file
Continue uploading a document(*1):
curl -C - -T file ftp://ftp.server.com/path/file
Continue downloading a document from a web server(*2):
curl -C - -o file http://www.server.com/
(*1) = This requires that the ftp server supports the non-standard command
SIZE. If it doesn't, curl will say so.
(*2) = This requires that the web server supports at least HTTP/1.1. If it
doesn't, curl will say so.
TIME CONDITIONS
HTTP allows a client to specify a time condition for the document it
requests. It is If-Modified-Since or If-Unmodified-Since. Curl allow you to
specify them with the -z/--time-cond flag.
For example, you can easily make a download that only gets performed if the
remote file is newer than a local copy. It would be made like:
curl -z local.html http://remote.server.com/remote.html
Or you can download a file only if the local file is newer than the remote
one. Do this by prepending the date string with a '-', as in:
curl -z -local.html http://remote.server.com/remote.html
You can specify a "free text" date as condition. Tell curl to only download
the file if it was updated since yesterday:
curl -z yesterday http://remote.server.com/remote.html
Curl will then accept a wide range of date formats. You always make the date
check the other way around by prepending it with a dash '-'.
DICT
For fun try
curl dict://dict.org/m:curl
curl dict://dict.org/d:heisenbug:jargon
curl dict://dict.org/d:daniel:web1913
Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define'
and 'lookup'. For example,
curl dict://dict.org/find:curl
Commands that break the URL description of the RFC (but not the DICT
protocol) are
curl dict://dict.org/show:db
curl dict://dict.org/show:strat
Authentication is still missing (but this is not required by the RFC)
LDAP
If you have installed the OpenLDAP library, curl can take advantage of it
and offer ldap:// support.
LDAP is a complex thing and writing an LDAP query is not an easy task. I do
advice you to dig up the syntax description for that elsewhere. Two places
that might suit you are:
Netscape's "Netscape Directory SDK 3.0 for C Programmer's Guide Chapter 10:
Working with LDAP URLs":
http://developer.netscape.com/docs/manuals/dirsdk/csdk30/url.htm
RFC 2255, "The LDAP URL Format" http://www.rfc-editor.org/rfc/rfc2255.txt
To show you an example, this is now I can get all people from my local LDAP
server that has a certain sub-domain in their email address:
curl -B "ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se"
If I want the same info in HTML format, I can get it by not using the -B
(enforce ASCII) flag.
ENVIRONMENT VARIABLES
Curl reads and understands the following environment variables:
http_proxy, HTTPS_PROXY, FTP_PROXY, GOPHER_PROXY
They should be set for protocol-specific proxies. General proxy should be
set with
ALL_PROXY
A comma-separated list of host names that shouldn't go through any proxy is
set in (only an asterisk, '*' matches all hosts)
NO_PROXY
If a tail substring of the domain-path for a host matches one of these
strings, transactions with that node will not be proxied.
The usage of the -x/--proxy flag overrides the environment variables.
NETRC
Unix introduced the .netrc concept a long time ago. It is a way for a user
to specify name and password for commonly visited ftp sites in a file so
that you don't have to type them in each time you visit those sites. You
realize this is a big security risk if someone else gets hold of your
passwords, so therefor most unix programs won't read this file unless it is
only readable by yourself (curl doesn't care though).
Curl supports .netrc files if told so (using the -n/--netrc and
--netrc-optional options). This is not restricted to only ftp,
but curl can use it for all protocols where authentication is used.
A very simple .netrc file could look something like:
machine curl.haxx.se login iamdaniel password mysecret
CUSTOM OUTPUT
To better allow script programmers to get to know about the progress of
curl, the -w/--write-out option was introduced. Using this, you can specify
what information from the previous transfer you want to extract.
To display the amount of bytes downloaded together with some text and an
ending newline:
curl -w 'We downloaded %{size_download} bytes\n' www.download.com
KERBEROS4 FTP TRANSFER
Curl supports kerberos4 for FTP transfers. You need the kerberos package
installed and used at curl build time for it to be used.
First, get the krb-ticket the normal way, like with the kauth tool. Then use
curl in way similar to:
curl --krb4 private ftp://krb4site.com -u username:fakepwd
There's no use for a password on the -u switch, but a blank one will make
curl ask for one and you already entered the real password to kauth.
TELNET
The curl telnet support is basic and very easy to use. Curl passes all data
passed to it on stdin to the remote server. Connect to a remote telnet
server using a command line similar to:
curl telnet://remote.server.com
And enter the data to pass to the server on stdin. The result will be sent
to stdout or to the file you specify with -o.
You might want the -N/--no-buffer option to switch off the buffered output
for slow connections or similar.
Pass options to the telnet protocol negotiation, by using the -t option. To
tell the server we use a vt100 terminal, try something like:
curl -tTTYPE=vt100 telnet://remote.server.com
Other interesting options for it -t include:
- XDISPLOC=<X display> Sets the X display location.
- NEW_ENV=<var,val> Sets an environment variable.
NOTE: the telnet protocol does not specify any way to login with a specified
user and password so curl can't do that automatically. To do that, you need
to track when the login prompt is received and send the username and
password accordingly.
PERSISTANT CONNECTIONS
Specifying multiple files on a single command line will make curl transfer
all of them, one after the other in the specified order.
libcurl will attempt to use persistant connections for the transfers so that
the second transfer to the same host can use the same connection that was
already initiated and was left open in the previous transfer. This greatly
decreases connection time for all but the first transfer and it makes a far
better use of the network.
Note that curl cannot use persistant connections for transfers that are used
in subsequence curl invokes. Try to stuff as many URLs as possible on the
same command line if they are using the same host, as that'll make the
transfers faster. If you use a http proxy for file transfers, practicly
all transfers will be persistant.
Persistant connections were introduced in curl 7.7.
MAILING LISTS
For your convenience, we have several open mailing lists to discuss curl,
its development and things relevant to this. Get all info at
http://curl.haxx.se/mail/. The lists available are:
curl-users
Users of the command line tool. How to use it, what doesn't work, new
features, related tools, questions, news, installations, compilations,
running, porting etc.
curl-library
Developers using or developing libcurl. Bugs, extensions, improvements.
curl-announce
Low-traffic. Only announcements of new public versions.
curl-and-PHP
Using the curl functions in PHP. Everything curl with a PHP angle. Or PHP
with a curl angle.
curl-commits
Receives notifications on all CVS commits done to the curl source module.
This can become quite a large amount of mails during intense development,
be aware. This is for us who like email...
curl-www-commits
Receives notifications on all CVS commits done to the curl www module
(basicly the web site). This can become quite a large amount of mails
during intense changing, be aware. This is for us who like email...
Please direct curl questions, feature requests and trouble reports to one of
these mailing lists instead of mailing any individual.
Download Driver Pack
After your driver has been downloaded, follow these simple steps to install it.
Expand the archive file (if the download file is in zip or rar format).
If the expanded file has an .exe extension, double click it and follow the installation instructions.
Otherwise, open Device Manager by right-clicking the Start menu and selecting Device Manager.
Find the device and model you want to update in the device list.
Double-click on it to open the Properties dialog box.
From the Properties dialog box, select the Driver tab.
Click the Update Driver button, then follow the instructions.
Very important: You must reboot your system to ensure that any driver updates have taken effect.
For more help, visit our Driver Support section for step-by-step videos on how to install drivers for every file type.