Reading about this question: In zsh how can I list all the environment variables?, I wondered, how can I list all the shell variables?

Also, does the distinction between shell variables and environment variables apply to shells other than zsh?

I am primarily interested in Bash and Zsh, but it would be great to know how to do this in other mainstream shells.

up vote 14 down vote accepted

List all shell variables

bash : use set -o posix ; set. The POSIX options is there to avoid outputting too much information, like function definitions.

zsh : use typeset

Shell variables and environment variables

An environment variable is available to exec()-ed child processes (as a copy. if parent process change the variable, the child environment is not updated). A non-environment variable is only available to the current running shell and fork()-ed subshells.

(completed thanks to comments)

  • declare -p do the same – Costas Dec 26 '14 at 14:02
  • The question also has an answer here : stackoverflow.com/questions/1305237/… – Uriel Dec 26 '14 at 14:05
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    set -o posix doesn't exist in zsh; set doesn't output function definitions. – vinc17 Dec 26 '14 at 14:33
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    set -o posix is a syntax error in most shells. – mikeserv Dec 26 '14 at 18:29
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    Shell variables are also available in child processes. The difference comes when the child process executes a new program: environment variables are passed along in exec, shell variables are not. – Barmar Dec 31 '14 at 19:03

There are many alternatives:

printenv

Print the values of the specified environment VARIABLE(s). If no VARIABLE is specified, print name and value pairs for them all.

env

env - run a program in a modified environment

export

Set an environment variable. Mark each name to be passed to child processes in the environment.....

-p Display output in a form that may be reused as input.

If no names are supplied, or if the `-p' option is given, a list of exported names is displayed.

set

is useful to get shell variables as well.

If you need extra info (integer, exported) you should instead use

typeset

export has an advantage, that its output can be immediately read back onto the shell.

Lastly, there is

compgen -v

Display possible completions depending on the options.

which shows all variables, shell and environment, without their value or extra info. You will have to echo $VARIABLE_NAME to find the variable value. But at least the list is complete. It belongs to bash, not zsh.

  • 1
    export has no advantage over set, at least, when it comes to quoting for shell re-entry. And printenv and env are not at all about shell variables, though these do often coincide with environment variables. – mikeserv Dec 26 '14 at 17:05

With zsh, you can use typeset, which gives more information than set, e.g. the type of the variables. You can still filter the output with grep or sed, depending on what you want. Environment variables are marked as exported in the output.

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