You can export shell variables using the export command.
Syntax
The syntax is as follows:[donotprint]
| Tutorial details | |
|---|---|
| Difficulty level | Easy |
| Root privileges | No |
| Requirements | None |
| Est. reading time | 1m |
export VAR
You can assign value before exporting using the following syntax:
export VAR=value
OR
VAR=value
export VAR
The export command will marks each VAR for automatic export to the environment of subsequently executed commands i.e. make the local shell variable VAR global.
Examples
To make the local shell variable called PATH type the following:
### export PATH ### export PATH=$PATH:/usr/local/bin echo "$PATH"
Set a new EDITOR variable:
export EDITOR=/usr/bin/vim
You need to add export statements to ~/.bash_profile or ~/.profile or /etc/profile file. This will export variables permanently:
$ vi ~/.bash_profile
Sample file
PATH=$PATH:$HOME/bin export PATH # set vim as a text editor export EDITOR=/usr/bin/vim # set colorful prompt export PS1='\[\e[1;32m\][\u@\h \W]\$\[\e[0m\] ' # set java_home export JAVA_HOME=/usr/local/jdk
To see all a list of all exported variables and functions, enter:
export -p
Sample outputs:
declare -x COLORTERM="gnome-terminal" declare -x DBUS_SESSION_BUS_ADDRESS="unix:abstract=/tmp/dbus-pODhldZ1lj,guid=6cfbd17d02f210f6de5e630b00000165" declare -x DESKTOP_SESSION="gnome" declare -x DISPLAY=":0.0" declare -x GDMSESSION="gnome" declare -x GDM_KEYBOARD_LAYOUT="us" declare -x GDM_LANG="en_IN" declare -x GNOME_DESKTOP_SESSION_ID="this-is-deprecated" declare -x GNOME_KEYRING_CONTROL="/tmp/keyring-oDL07q" declare -x GNOME_KEYRING_PID="2708" declare -x GPG_AGENT_INFO="/tmp/seahorse-PBDijt/S.gpg-agent:2777:1" declare -x GTK_MODULES="canberra-gtk-module" declare -x GTK_RC_FILES="/etc/gtk/gtkrc:/home/vivek/.gtkrc-1.2-gnome2" declare -x HOME="/home/vivek" declare -x LANG="en_IN" declare -x LANGUAGE="en_IN:en" declare -x LOGNAME="vivek" declare -x LS_COLORS="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:" declare -x OLDPWD declare -x ORBIT_SOCKETDIR="/tmp/orbit-vivek" declare -x PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games" declare -x PWD="/tmp/n" declare -x SESSION_MANAGER="local/wks01:@/tmp/.ICE-unix/2727,unix/wks01:/tmp/.ICE-unix/2727" declare -x SHELL="/bin/bash" declare -x SHLVL="1" declare -x SSH_AGENT_PID="2763" declare -x SSH_AUTH_SOCK="/tmp/keyring-oDL07q/ssh" declare -x TERM="xterm" declare -x USER="vivek" declare -x USERNAME="vivek" declare -x WINDOWID="73400323" declare -x WINDOWPATH="7" declare -x XAUTHORITY="/var/run/gdm3/auth-for-vivek-DSw31c/database" declare -x XDG_DATA_DIRS="/usr/share/gnome:/usr/share/gdm/:/usr/local/share/:/usr/share/" declare -x XDG_SESSION_COOKIE="6cff67927ad82fca095a44640000001f-1336294442.327911-838315070"
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Could you comment on the following unexpected (to me) behavior of the export command in bash and dash. Note the punctuation or lack thereof.
($ = prompt, # = output)
standard/normal cases:
$ echo -$bar -$foo
# – –
$ export bar=foo; echo -$bar
# -foo
$ echo -$bar
# -foo
$ bar=fu; export bar; echo -$bar
# -fu
$ echo -$bar
# -fu
$ bar=foo; echo -$bar
# -foo
$ echo -$bar
# -foo
And now for something different:
$ foo=bar echo -$foo
# –
$ foo\=bar ; echo -$foo
# fu=bar: command not found
# –
$ echo -$foo
# –
$ foo=bar export foo; echo -$foo
# -bar
$ foo=bear; export foo; echo -$foo
# -bear
$ `foo=bar` echo -$foo
# -bar
My question is basically, why does the shell appear to be automatically expanding a variable assignment (or “silently executing an assignment”) prior to an export, but not prior to another command like echo? Is export “special”? What other circumstances have behavior like export?
The reason this came up is because I’ve seen a couple of example scripts that have a line similar to
/bin/sh -c ‘DISPLAY=:0 some_GUI_program’
Should this do anything in general? If so, why?
(I’ve been using linux on and off for about 15 years now, including at one point administering a production linux box, but still feel like a complete n00b)
in samples file
“# set vim as a text editor
export EDITOR=/usr/bin/bin”
you mean /usr/bin/vim
Thanks for the heads up!
Hi,
Am porting my code base to run with a different toolchain. This new toolchain has the standard libraries defined in /usr/. When I export this path as “export PATH=$PATH:/usr/bin”, this path is added to the existing variable PATH. The output looked like,
declare -x PATH=”/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin”
So my understanding is that, the compiler still searches in /usr/local/sbin or /usr/local/bin first and uses libraries from there.
But I want my compiler to look into toolchain_path for all standard libraries.
How do I achieve it..??
Thanks,
Bhargavi
Simply swap it round to “export PATH=/usr/bin:$PATH”
But if you’re specifically talking about the *compiler* search path, rather than the *shell* search path, then this is something different and you’ll have to check your compiler’s manual.