| <!-- Copyright (C) Daniel Stenberg, <[email protected]>, et al. --> | |
| <!-- SPDX-License-Identifier: curl --> | |
| # ENVIRONMENT | |
| The environment variables can be specified in lower case or upper case. The | |
| lower case version has precedence. `http_proxy` is an exception as it is only | |
| available in lower case. | |
| Using an environment variable to set the proxy has the same effect as using | |
| the --proxy option. | |
| ## `http_proxy` [protocol://]<host>[:port] | |
| Sets the proxy server to use for HTTP. | |
| ## `HTTPS_PROXY` [protocol://]<host>[:port] | |
| Sets the proxy server to use for HTTPS. | |
| ## `[url-protocol]_PROXY` [protocol://]<host>[:port] | |
| Sets the proxy server to use for [url-protocol], where the protocol is a | |
| protocol that curl supports and as specified in a URL. FTP, FTPS, POP3, IMAP, | |
| SMTP, LDAP, etc. | |
| ## `ALL_PROXY` [protocol://]<host>[:port] | |
| Sets the proxy server to use if no protocol-specific proxy is set. | |
| ## `NO_PROXY` <comma-separated list of hosts/domains> | |
| list of hostnames that should not go through any proxy. If set to an asterisk | |
| '*' only, it matches all hosts. Each name in this list is matched as either a | |
| domain name which contains the hostname, or the hostname itself. | |
| This environment variable disables use of the proxy even when specified with | |
| the --proxy option. That is | |
| NO_PROXY=direct.example.com curl -x http://proxy.example.com | |
| http://direct.example.com | |
| accesses the target URL directly, and | |
| NO_PROXY=direct.example.com curl -x http://proxy.example.com | |
| http://somewhere.example.com | |
| accesses the target URL through the proxy. | |
| The list of hostnames can also be include numerical IP addresses, and IPv6 | |
| versions should then be given without enclosing brackets. | |
| IP addresses can be specified using CIDR notation: an appended slash and | |
| number specifies the number of "network bits" out of the address to use in the | |
| comparison (added in 7.86.0). For example "192.168.0.0/16" would match all | |
| addresses starting with "192.168". | |
| ## `APPDATA` <dir> | |
| On Windows, this variable is used when trying to find the home directory. If | |
| the primary home variable are all unset. | |
| ## `COLUMNS` <terminal width> | |
| If set, the specified number of characters is used as the terminal width when | |
| the alternative progress-bar is shown. If not set, curl tries to figure it out | |
| using other ways. | |
| ## `CURL_CA_BUNDLE` <file> | |
| If set, it is used as the --cacert value. This environment variable is ignored | |
| if Schannel is used as the TLS backend. | |
| ## `CURL_HOME` <dir> | |
| If set, is the first variable curl checks when trying to find its home | |
| directory. If not set, it continues to check *XDG_CONFIG_HOME* | |
| ## `CURL_SSL_BACKEND` <TLS backend> | |
| If curl was built with support for "MultiSSL", meaning that it has built-in | |
| support for more than one TLS backend, this environment variable can be set to | |
| the case insensitive name of the particular backend to use when curl is | |
| invoked. Setting a name that is not a built-in alternative makes curl stay | |
| with the default. | |
| SSL backend names (case-insensitive): **bearssl**, **gnutls**, **mbedtls**, | |
| **openssl**, **rustls**, **schannel**, **secure-transport**, **wolfssl** | |
| ## `HOME` <dir> | |
| If set, this is used to find the home directory when that is needed. Like when | |
| looking for the default .curlrc. *CURL_HOME* and *XDG_CONFIG_HOME* | |
| have preference. | |
| ## `QLOGDIR` <directory name> | |
| If curl was built with HTTP/3 support, setting this environment variable to a | |
| local directory makes curl produce **qlogs** in that directory, using file | |
| names named after the destination connection id (in hex). Do note that these | |
| files can become rather large. Works with the ngtcp2 and quiche QUIC backends. | |
| ## `SHELL` | |
| Used on VMS when trying to detect if using a **DCL** or a **Unix** shell. | |
| ## `SSL_CERT_DIR` <dir> | |
| If set, it is used as the --capath value. This environment variable is ignored | |
| if Schannel is used as the TLS backend. | |
| ## `SSL_CERT_FILE` <path> | |
| If set, it is used as the --cacert value. This environment variable is ignored | |
| if Schannel is used as the TLS backend. | |
| ## `SSLKEYLOGFILE` <filename> | |
| If you set this environment variable to a filename, curl stores TLS secrets | |
| from its connections in that file when invoked to enable you to analyze the | |
| TLS traffic in real time using network analyzing tools such as Wireshark. This | |
| works with the following TLS backends: OpenSSL, LibreSSL (TLS 1.2 max), | |
| BoringSSL, GnuTLS and wolfSSL. | |
| ## `USERPROFILE` <dir> | |
| On Windows, this variable is used when trying to find the home directory. If | |
| the other, primary, variable are all unset. If set, curl uses the path | |
| **"$USERPROFILE\Application Data"**. | |
| ## `XDG_CONFIG_HOME` <dir> | |
| If *CURL_HOME* is not set, this variable is checked when looking for a | |
| default .curlrc file. | |