Menu
in my script.sh:
aa=$@
bb=$*
echo $aa
echo $bb
when running it:
source script.sh a b c d e f g
I get:
a b c d e f g
a b c d e f g
What is the difference between $@ and $* ?
581
$0 Stores the first word of the entered command (the name of the shell program). $* Stores all the arguments that were entered on the command line ($1 $2 ...). "$@" Stores all the arguments that were entered on the command line, individually quoted ("$1" "$2" ...).
The difference between "$*" and $* is that the quotes keep the expansion of $* as a single string while having no quotes allows the parts of $* to be treated as individual items. This is the general meaning of double quotes; the behaviour is not specific to $* and $@.
The $@ holds list of all arguments passed to the script. The $* holds list of all arguments passed to the script.
$@ refers to all of a shell script's command-line arguments. $1 , $2 , etc., refer to the first command-line argument, the second command-line argument, etc. Place variables in quotes if the values might have spaces in them.
There are no difference between $* and $@, but there is a difference between "$@" and "$*".
$ cat 1.sh
mkdir "$*"
$ cat 2.sh
mkdir "$@"
$ sh 1.sh a "b c" d
$ ls -l
total 12
-rw-r--r-- 1 igor igor 11 mar 24 10:20 1.sh
-rw-r--r-- 1 igor igor 11 mar 24 10:20 2.sh
drwxr-xr-x 2 igor igor 4096 mar 24 10:21 a b c d
We gave three arguments to the script (a, b c and d) but in "$*" they all were merged into one argument a b c d.
$ sh 2.sh a "b c" d
$ ls -l
total 24
-rw-r--r-- 1 igor igor 11 mar 24 10:20 1.sh
-rw-r--r-- 1 igor igor 11 mar 24 10:20 2.sh
drwxr-xr-x 2 igor igor 4096 mar 24 10:21 a
drwxr-xr-x 2 igor igor 4096 mar 24 10:21 a b c d
drwxr-xr-x 2 igor igor 4096 mar 24 10:21 b c
drwxr-xr-x 2 igor igor 4096 mar 24 10:21 d
You can see here, that "$*" means always one single argument, and "$@" contains as many arguments, as the script had. "$@" is a special token which means "wrap each individual argument in quotes". So a "b c" d becomes (or rather stays) "a" "b c" "d" instead of "a b c d" ("$*") or "a" "b" "c" "d" ($@ or $*).
Also, I would recommend this beautiful reading on the theme:
http://tldp.org/LDP/abs/html/internalvariables.html#ARGLIST
139
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
