cURL cURL > Docs > Features

Features -- what can curl do

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FEATURES
 
curl tool
 - config file support
 - multiple URLs in a single command line
 - range "globbing" support: [0-13], {one,two,three}
 - multiple file upload on a single command line
 - custom maximum transfer rate
 - redirectable stderr
 - metalink support (*13)
 
libcurl
 - full URL syntax with no length limit
 - custom maximum download time
 - custom least download speed acceptable
 - custom output result after completion
 - guesses protocol from host name unless specified
 - uses .netrc
 - progress bar with time statistics while downloading
 - "standard" proxy environment variables support
 - compiles on win32 (reported builds on 40+ operating systems)
 - selectable network interface for outgoing traffic
 - IPv6 support on unix and Windows
 - persistent connections
 - socks 4 + 5 support, with or without local name resolving
 - supports user name and password in proxy environment variables
 - operations through proxy "tunnel" (using CONNECT)
 - support for large files (>2GB and >4GB) during upload and download
 - replaceable memory functions (malloc, free, realloc, etc)
 - asynchronous name resolving (*6)
 - both a push and a pull style interface
 - international domain names (*11)
 
HTTP
 - HTTP/1.1 compliant (optionally uses 1.0)
 - GET
 - PUT
 - HEAD
 - POST
 - Pipelining
 - multipart formpost (RFC1867-style)
 - authentication: Basic, Digest, NTLM (*9) and Negotiate (SPNEGO) (*3)
   to server and proxy
 - resume (both GET and PUT)
 - follow redirects
 - maximum amount of redirects to follow
 - custom HTTP request
 - cookie get/send fully parsed
 - reads/writes the netscape cookie file format
 - custom headers (replace/remove internally generated headers)
 - custom user-agent string
 - custom referrer string
 - range
 - proxy authentication
 - time conditions
 - via http-proxy
 - retrieve file modification date
 - Content-Encoding support for deflate and gzip
 - "Transfer-Encoding: chunked" support in uploads
 - data compression (*12)
 - HTTP/2 (*5)
 
HTTPS (*1)
 - (all the HTTP features)
 - using client certificates
 - verify server certificate
 - via http-proxy
 - select desired encryption
 - force usage of a specific SSL version (SSLv2 (*7), SSLv3 (*10) or TLSv1)
 
FTP
 - download
 - authentication
 - Kerberos 5 (*14)
 - active/passive using PORT, EPRT, PASV or EPSV
 - single file size information (compare to HTTP HEAD)
 - 'type=' URL support
 - dir listing
 - dir listing names-only
 - upload
 - upload append
 - upload via http-proxy as HTTP PUT
 - download resume
 - upload resume
 - custom ftp commands (before and/or after the transfer)
 - simple "range" support
 - via http-proxy
 - all operations can be tunneled through a http-proxy
 - customizable to retrieve file modification date
 - no dir depth limit
 
FTPS (*1)
 - implicit ftps:// support that use SSL on both connections
 - explicit "AUTH TLS" and "AUTH SSL" usage to "upgrade" plain ftp://
   connection to use SSL for both or one of the connections
 
SCP (*8)
 - both password and public key auth
 
SFTP (*8)
 - both password and public key auth
 - with custom commands sent before/after the transfer
 
TFTP
 - download
 - upload
 
TELNET
 - connection negotiation
 - custom telnet options
 - stdin/stdout I/O
 
LDAP (*2)
 - full LDAP URL support
 
DICT
 - extended DICT URL support
 
FILE
 - URL support
 - upload
 - resume
 
SMB
 - SMBv1 over TCP and SSL
 - download
 - upload
 - authentication with NTLMv1
 
SMTP
 - authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM (*9) and Kerberos 5
   (*4)
 - send e-mails
 - mail from support
 - mail size support
 - mail auth support for trusted server-to-server relaying
 - multiple recipients
 - via http-proxy
 
SMTPS (*1)
 - implicit smtps:// support
 - explicit "STARTTLS" usage to "upgrade" plain smtp:// connections to use SSL
 - via http-proxy
 
POP3
 - authentication: Clear Text, APOP and SASL
 - SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM (*9) and
   Kerberos 5 (*4)
 - list e-mails
 - retrieve e-mails
 - enhanced command support for: CAPA, DELE, TOP, STAT, UIDL and NOOP via
   custom requests
 - via http-proxy
 
POP3S (*1)
 - implicit pop3s:// support
 - explicit "STLS" usage to "upgrade" plain pop3:// connections to use SSL
 - via http-proxy
 
IMAP
 - authentication: Clear Text and SASL
 - SASL based authentication: Plain, Login, CRAM-MD5, Digest-MD5, NTLM (*9) and
   Kerberos 5 (*4)
 - list the folders of a mailbox
 - select a mailbox with support for verifying the UIDVALIDITY
 - fetch e-mails with support for specifying the UID and SECTION
 - upload e-mails via the append command
 - enhanced command support for: EXAMINE, CREATE, DELETE, RENAME, STATUS,
   STORE, COPY and UID via custom requests
 - via http-proxy
 
IMAPS (*1)
 - implicit imaps:// support
 - explicit "STARTTLS" usage to "upgrade" plain imap:// connections to use SSL
 - via http-proxy
 
FOOTNOTES
=========
 
  *1 = requires OpenSSL, GnuTLS, NSS, yassl, axTLS, PolarSSL, WinSSL (native
       Windows), Secure Transport (native iOS/OS X) or GSKit (native IBM i)
  *2 = requires OpenLDAP
  *3 = requires a GSS-API implementation (such as Heimdal or MIT Kerberos) or
       SSPI (native Windows)
  *4 = requires a GSS-API implementation, however, only Windows SSPI is
       currently supported
  *5 = requires nghttp2 and possibly a recent TLS library
  *6 = requires c-ares
  *7 = requires OpenSSL, NSS, GSKit, WinSSL or Secure Transport; GnuTLS, for
       example, only supports SSLv3 and TLSv1
  *8 = requires libssh2
  *9 = requires OpenSSL, GnuTLS, NSS, yassl, Secure Transport or SSPI (native
       Windows)
  *10 = requires any of the SSL libraries in (*1) above other than axTLS, which
        does not support SSLv3
  *11 = requires libidn or Windows
  *12 = requires libz
  *13 = requires libmetalink, and either an Apple or Microsoft operating
        system, or OpenSSL, or GnuTLS, or NSS
  *14 = requires a GSS-API implementation (such as Heimdal or MIT Kerberos)