In tcsh, I have the following script working:
#!/bin/tcsh setenv X_ROOT /some/specified/path setenv XDB ${X_ROOT}/db setenv PATH ${X_ROOT}/bin:${PATH} xrun -d xdb1 -i $1 > $2 What is the equivalent to the tcsh setenv function in Bash?
Is there a direct analog? The environment variables are for locating the executable.
5 Answers
export VAR=value will set VAR to value. Enclose it in single quotes if you want spaces, like export VAR='my val'. If you want the variable to be interpolated, use double quotes, like export VAR="$MY_OTHER_VAR".
The reason people often suggest writing
VAR=value export VAR instead of the shorter
export VAR=value is that the longer form works in more different shells than the short form. If you know you're dealing with bash, either works fine, of course.
Set a local and environment variable using Bash on Linux
Check for a local or environment variables for a variable called LOL in Bash:
el@server /home/el $ set | grep LOL el@server /home/el $ el@server /home/el $ env | grep LOL el@server /home/el $ Sanity check, no local or environment variable called LOL.
Set a local variable called LOL in local, but not environment. So set it:
el@server /home/el $ LOL="so wow much code" el@server /home/el $ set | grep LOL LOL='so wow much code' el@server /home/el $ env | grep LOL el@server /home/el $ Variable 'LOL' exists in local variables, but not environment variables. LOL will disappear if you restart the terminal, logout/login or run exec bash.
Set a local variable, and then clear out all local variables in Bash
el@server /home/el $ LOL="so wow much code" el@server /home/el $ set | grep LOL LOL='so wow much code' el@server /home/el $ exec bash el@server /home/el $ set | grep LOL el@server /home/el $ You could also just unset the one variable:
el@server /home/el $ LOL="so wow much code" el@server /home/el $ set | grep LOL LOL='so wow much code' el@server /home/el $ unset LOL el@server /home/el $ set | grep LOL el@server /home/el $ Local variable LOL is gone.
Promote a local variable to an environment variable:
el@server /home/el $ DOGE="such variable" el@server /home/el $ export DOGE el@server /home/el $ set | grep DOGE DOGE='such variable' el@server /home/el $ env | grep DOGE DOGE=such variable Note that exporting makes it show up as both a local variable and an environment variable.
Exported variable DOGE above survives a Bash reset:
el@server /home/el $ exec bash el@server /home/el $ env | grep DOGE DOGE=such variable el@server /home/el $ set | grep DOGE DOGE='such variable' Unset all environment variables:
You have to pull out a can of Chuck Norris to reset all environment variables without a logout/login:
el@server /home/el $ export CAN="chuck norris" el@server /home/el $ env | grep CAN CAN=chuck norris el@server /home/el $ set | grep CAN CAN='chuck norris' el@server /home/el $ env -i bash el@server /home/el $ set | grep CAN el@server /home/el $ env | grep CAN You created an environment variable, and then reset the terminal to get rid of them.
Or you could set and unset an environment variable manually like this:
el@server /home/el $ export FOO="bar" el@server /home/el $ env | grep FOO FOO=bar el@server /home/el $ unset FOO el@server /home/el $ env | grep FOO el@server /home/el $ VAR=value sets VAR to value.
After that export VAR will give it to child processes too.
export VAR=value is a shorthand doing both.
I think you're looking for export - though I could be wrong.. I've never played with tcsh before. Use the following syntax:
export VARIABLE=value 
