Bash – Why does $SHELL point to /bin/bash if running zsh inside bash

bashenvironment-variablesshellzsh

If I run zsh inside bash (on macOS Sierra), why does $SHELL still point to /bin/bash, rather then /bin/zsh?

$ echo $SHELL
/bin/bash
$ zsh
% echo $SHELL
/bin/bash

Best Answer

$SHELL should point to your login shell, not current shell. As in, grep $USER /etc/passwd - it shows you your login shell which is probably /bin/bash.

You need to change shell with chsh to make the change permanent.

Related Solutions

Bash – Unique Features of bash compared to zsh

zsh is for vulcans. ;-)

Seriously: bash 4.0 has some features previously only found in zsh, like ** globbing:

% ls /usr/src/**/Makefile

is equivalent to:

% find /usr/src -name "Makefile"

but obviously more powerful.

In my experience bash's programmable completion performs a bit better than zsh's, at least for some cases (completing debian packages for aptitude for example).

bash has Alt + . to insert !$

zsh has expansion of all variables, so you can use e.g.



% rm !$<Tab>


for this. zsh can also expand a command in backtics, so

% cat `echo blubb | sed 's/u/a/'`<Tab>


yields

% cat blabb


I find it very useful to expand rm *, as you can see what would be removed and can maybe remove one or two files from the commmand to prevent them from being deleted.

Also nice: using the output from commands for other commands that do not read from stdin but expect a filename:

% diff <(sort foo) <(sort bar)


From what I read bash-completion also supports completing remote filenames over ssh if you use ssh-agent, which used to be a good reason to switch to zsh.

Aliases in zsh can be defined to work on the whole line instead of just at the beginning:

% alias -g ...="../.."
% cd ...

Bash: variable loses value at end of while read loop

See argument @ Bash FAQ entry #24: "I set variables in a loop. Why do they suddenly disappear after the loop terminates? Or, why can't I pipe data to read?" (most recently archived here).

Summary: This is only supported from bash 4.2 and up. You need to use different ways like command substitutions instead of a pipe if you are using bash.

Best Answer

Related Solutions

Bash – Unique Features of bash compared to zsh

Bash: variable loses value at end of while read loop

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