How to check what shell I am using in a terminal? What is the shell I am using in MacOS?
Several ways, from most to least reliable (and most-to-least "heavy"):
ps -p$$ -ocmd=
. (On Solaris, this may need to befname
instead ofcmd
. On OSX and on BSD should becommand
instead ofcmd
.)- Check for
$BASH_VERSION
,$ZSH_VERSION
, and other shell-specific variables. - Check
$SHELL
; this is a last resort, as it specifies your default shell and not necessarily the current shell.
-
4
-
I don't like
$0
because it's more complicated: (1) it may be just the basename, (2) it may have '-' on the front to designate it as a login shell. – geekosaur Mar 18 '11 at 2:44 -
-
1@geekosaur: maybe so, but
$0
still seems more useful than$SHELL
: wouldn't you agree? You could always pipe it throughsed
to remove the '-'. – iconoclast Aug 29 '12 at 21:49 -
2If you're running
tcsh
,$tcsh
and$version
will be set. These are shell variables, not environment variables. If you're running a non-tcsh version ofcsh
, I don't think there are any distinctive variables. And of course the syntax used to check variables differs between csh/tcsh on the one hand, and sh/ksh/bash/zsh on the other. – Keith Thompson Mar 18 '14 at 1:51
I've found that the following works in the four shells I have installed on my system (bash, dash, zsh, csh):
$ ps -p $$
The following works on zsh, bash, and dash, but not on csh:
$ echo $0
-
2
-
I think that @jiliagre's answer is probably would I would use today. On fish
%self
can be used in place of$$
– Steven D Aug 27 '16 at 23:00
As the question asks for the shell used and does not talk about the potential arguments passed to it, here is a way that avoid showing them:
$ ps -o comm= -p $$
ksh93
A note about some lighter implementations (Android phones, busybox, etc.): ps
doesn't always have support for the -p
switch, but you can accomplish the search with a command like ps | grep "^$$ "
. (This grep
regex will uniquely identify the PID, so there will not be any false positives.
-
7
ps | grep $$
can still give false positives if, for example, your current process is1234
and there's a process12345
. – Keith Thompson Mar 18 '14 at 1:48
There are two really simple ways:
Using ps command:
ps -o comm= $$
or
ps -h -o comm -p $$
where:
-h
or finishing all options with=
for not showing any header.-o comm
for showing only the process basename (bash
instead of/bin/bash
).-p <PID>
list only process whith PID form list suplied.
Using the /proc process information pseudo-file system:
cat /proc/$$/comm
This option behaves exactly as the
ps
command above.or
readlink /proc/$$/exe
This
/proc/PID/exe
links to the file being executed, which in this case would point to /bin/bash, /bin/ksh, etc.For getting only the name of the shell you can just use
basename $(readlink /proc/$$/exe)
This is the only option that will always give the same result even if you are in an script, sourced code, or terminal, as links to the binary of the shell interpreter in use.
Warning You must be aware that this will show the ultimate binary, so ksh may be linked to ksh93 or sh to bash.
The usage of /proc
is really useful via the /proc/self
, which links to the PID of the current command.
A mix of all the other answers, compatible with Mac (comm), Solaris (fname) and Linux (cmd):
ps -p$$ -o cmd="",comm="",fname="" 2>/dev/null | sed 's/^-//' | grep -oE '\w+' | head -n1
-
this gives me my current directory name; also, under
csh
andtcsh
it gives meAmbiguous output redirect.
– iconoclast Aug 7 '15 at 0:17
If you have it saved in your environment variables you can use the following:
echo $SHELL
-
That will most likely return the pathname of the shell executable of your login shell. It is not certain that the login shell is what you are currently running though. – Kusalananda♦ Apr 10 at 6:39
The pid of the running shell is given by the var $$ (in most shells).
whichsh="`ps -o pid,args| awk '$1=='"$$"'{print $2}'`"
echo "$whichsh"
Using backticks to make jsh (Heirlomm shell) work.
In many shells the direct test of ps -o args= -p $$
works, but busybox ash
fails on that (solved).
The check that $1
must be equal to $$
removes most false positives.
The last ;:
are used to keep the shell running for ksh and zsh.
Tests on more systems will help, please make a comment if it doesn't work for you.
Does not work in csh
type of shells.
-
On OS/X, in my tests, I get at least 3 lines, one for the shell, one for
/usr/lib/dyld
, one for/private/var/db/dyld/dyld_shared_cache_x86_64
. – Stéphane Chazelas Sep 7 '15 at 16:12 -
-
@StéphaneChazelas Maybe it is better now? – user79743 Feb 25 '16 at 22:29
I set $MYSHELL
for future tests in my shell-agnostic ~/.aliases
:
unset MYSHELL
if [ -n "$ZSH_VERSION" ] && type zstyle >/dev/null 2>&1; then # zsh
MYSHELL=`command -v zsh`
elif [ -x "$BASH" ] && shopt -q >/dev/null 2>&1; then # bash
MYSHELL=`command -v bash`
elif [ -x "$shell" ] && which setenv |grep builtin >/dev/null; then # tcsh
echo "DANGER: this script is likely not compatible with C shells!"
sleep 5
setenv MYSHELL "$shell"
fi
# verify
if [ ! -x "$MYSHELL" ]; then
MYSHELL=`command -v "$(ps $$ |awk 'NR == 2 { print $NF }')"`
[ -x "$MYSHELL" ] || MYSHELL="${SHELL:-/bin/sh}" # default if verify fails
fi
The tcsh
section is likely unwise to roll into a POSIX-style script since it's so radically different (thus the warning and five second pause). (For one, csh
-style shells can't do 2>/dev/null
or >&2
, as noted in the famous Csh Programming Considered Harmful rant.)
You can simply use echo $0
command to check which shell you are using and <name_of_the_shell> --version
to check the version of the shell. (eg. bash --version
).
This works too:
env | grep SHELL
-
3
echo #SHELL
is not quite it. See # 3 in the Answer by geekosaur. – Basil Bourque Feb 4 '17 at 23:18xterm -e /bin/cat
but I am not happy calling/bin/cat
a shell. – Basile Starynkevitch Aug 24 '17 at 10:26