Global environment variables in a shell script
ShellScriptingEnvironment VariablesShell Problem Overview
How to set a global environment variable in a bash script?
If I do stuff like
#!/bin/bash
FOO=bar
...or
#!/bin/bash
export FOO=bar
...the vars seem to stay in the local context, whereas I'd like to keep using them after the script has finished executing.
Shell Solutions
Solution 1 - Shell
Run your script with .
. myscript.sh
This will run the script in the current shell environment.
export governs which variables will be available to new processes, so if you say
FOO=1
export BAR=2
./runScript.sh
then $BAR will be available in the environment of runScript.sh, but $FOO will not.
Solution 2 - Shell
When you run a shell script, it's done in a sub-shell so it cannot affect the parent shell's environment. You want to source the script by doing:
. ./setfoo.sh
This executes it in the context of the current shell, not as a sub shell.
From the bash man page:
> . filename [arguments]
> source filename [arguments]
>
> Read and execute commands from filename in the current shell
> environment and return the exit status of the last command executed
> from filename.
>
> If filename does not contain a slash, file names in PATH are used to
> find the directory containing filename.
>
> The file searched for in PATH need not be executable. When bash is not
> in POSIX mode, the current directory is searched if no file is found
> in PATH.
>
> If the sourcepath option to the shopt builtin command is turned off,
> the PATH is not searched.
>
> If any arguments are supplied, they become the positional parameters
> when filename is executed.
>
> Otherwise the positional parameters are unchanged. The return status
> is the status of the last command exited within the script (0 if no
> commands are executed), and false if filename is not found or cannot
> be read.
Solution 3 - Shell
source myscript.sh is also feasible.
Description for linux command source:
source is a Unix command that evaluates the file following the command,
as a list of commands, executed in the current context
Solution 4 - Shell
#!/bin/bash
export FOO=bar
or
#!/bin/bash
FOO=bar
export FOO
man export:
The shell shall give the export attribute to the variables corresponding to the specified names, which shall cause them to be in the environment of subsequently executed commands. If the name of a variable is followed by = word, then the value of that variable shall be set to word.
Solution 5 - Shell
FOO=bar
export FOO