This document discusses cURL, a command line tool and library for transferring data with URLs. It can be used to download files from FTP, FTPS, SCP, SFTP, TFTP, TELNET, and DICT protocols. It supports various authentication methods, proxies, cookies, SSL certificates, HTTP requests, uploads, and more. Examples are provided for using cURL to download and upload files, trace requests, set headers, log into websites and perform additional requests, and update dynamic DNS entries. It emphasizes that cURL allows scripting complex URL transfers and interactions through a single tool.

1. cURL
Akilan RAkilan R
akilan@tcoe.iitm.ac.in

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cURL?
– http://curl.haxx.se/

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cURL?
curl - transfer a URL
– http://curl.haxx.se/

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cURL :
– http://curl.haxx.se/

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User + password
Authentication
– Basic
– Digest
– NTLM
– Negotiate
– Kerberos
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Proxy
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Resume
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Cookies
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Proxy tunneling
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SSL certs
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HTTP range requests
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UA spoofing
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Wireshark
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gzip/deflate
cURL

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The real cURL

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HTTP
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HTTPS
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FTP
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FTPS
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SCP
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SFTP
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TFTP
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TELNET
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LDAP
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DICT
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POP
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SMTP
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RTMP
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RTSP
The real cURL

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What it isn't

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What it isn't

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But you can build one...

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Get a file
$ curl protocol://example.com/path/to/file
$ curl ftps://example.com/path/to/file
$ curl blah://user:pass@example.com:port/file
$ curl -u user:pass scp://example.com/~/personal.txt

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more...
$ curl -u user:pass -x proxy:3128
http://example.com/file
$ curl -u user:pass -x proxy:3128 -u user:pass
http://example.com/file

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Upload
$ curl -T filename http://www.upload.com/myfile
$ curl -T – ftp://ftp.upload.com//myfile

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Trace
$ curl --trace tracefile http://www.example.com/
$ curl --trace-ascii tracefile http://www.example.com/

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Few cool features...
$ curl -e www.coolsite.com http://www.showme.com/
$ curl -A 'Konqueror/1.0' http://www.example.com/
$ curl --limit-rate 10K www.far-away-site.com

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Few cool features...
$ curl -H "X-some-header: yes" www.example.com
$ curl --interface eth0:1 http://www.netscape.com
$ curl -E /path/to/cert.pem:password
https://secure.site.com
$curl telnet://remote.server.com

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FTP
$ curl -T – ftp://ftp.upload.com//myfile
$ curl --ftp-port <address> ftp://ftp.upload.com/myfile
$ curl -O ftp://download.com/coolfile -Q '-DELE
coolfile'

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SMTP
$ curl --mail-rcpt <address>
--mail-from <akilan27@gmail.com> -u akilan27:pass
--ssl smtp://smtp.gmail.com

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HTTP
$ curl “ google.com/search?q=ilugc”
Get requests are simple:

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HTTP
$ curl --user-agent "Mozilla/4.73 [en] (X11; U; Linux
2.2.15 i686)" “ google.com/search?q=ilugc”
Get requests are simple:

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HTTP
$ curl --user-agent "Mozilla/5.0 [en] (X11; U; Linux
2.6.28 i386)" “ http://google.com/search?q=ilugc”
Get requests are simple:
Post requests are also simple with curl. ;-)
$ curl --data-urlencode input=value http://example.com/cgi

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HTTP
$ curl --proxy-user proxyuser:proxypassword curl.haxx.se
Proxy
Post requests are also simple with curl. ;-)
$ curl --data-urlencode input=value http://example.com/cgi

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Scripting cURL
curl
http://username:password@members.dyndns.org/nic/update?
hostname=yourhostname&myip=ipaddress&wildcard=NOCHG&mx=N
OCHG&backmx=NOCHG
Update your dyndns:

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Scripting cURL
curl -c mycookie --data-urlencode email=foo@bar.com
--data-urlencode pwd=password
http://example.com/ValidateEntry.php
Login to a website and perform requests

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Scripting cURL
curl -c cookie --data-urlencode email=foo@bar.com
--data-urlencode pwd=password
http://example.com/ValidateEntry.php
curl -b cookie --data-urlencode uid=bar – data-urlencode
action=del http://example.com/usermanip.php
Login to a website and perform requests

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Scripting cURL
curl -c cookie --data-urlencode email=foo@bar.com
--data-urlencode pwd=password
http://example.com/ValidateEntry.php
curl -b cookie --data-urlencode uid=bar – data-urlencode
action=del http://example.com/usermanip.php
rm cookie
Login to a website and perform requests