Difference between $* and $@ in Bash [duplicate]

Question

Who can help to give a shell script example to show the difference between $* and $@?

The following is my script, but it can't tell the difference. Anybody can give a good example?

$ cat internalVar.sh #!/bin/bash # internalVar.sh var1 var2 echo "\$? = " $? export IFS="_" echo "\$@ = " $@ " == several parameters?" j=1 for i in $@ do echo "var $j = $i" j=$((j+1)) done echo "\$* = " $* " == a single string" j=1 for i in $* do echo "var $j = $i" j=$((j+1)) done echo "\$# = " $# echo "\$0 = " $0 echo "\$$ = " $$ $ export IFS="c" [$ ./internalVar.sh par1 "par meter 2" par3 $? = 0 $@ = par1 par meter 2 par3 == several parameters? var 1 = par1 var 2 = par meter 2 var 3 = par3 $* = par1 par meter 2 par3 == a single string var 1 = par1 var 2 = par meter 2 var 3 = par3 $# = 3 $0 = ./internalVar.sh $$ = 4638

Your script can't tell the difference because it's not using appropriate quotes. Without quoting correctly, there is no difference (and you get a whole lot of bugs). — Charles Duffy
– Charles Duffy, Commented May 6, 2016 at 1:41
@CharlesDuffy Duh, of course there is a duplicate. I must have thought "it's not asking about var = val, it must be new ;) — Benjamin W.
– Benjamin W., Commented May 6, 2016 at 1:46

Benjamin W. · Accepted Answer · 2016-05-06 01:39:49Z

How about this:

$ set 'arg1a arg1b' 'arg2a arg2b' 'arg3a arg3b' $ for arg in "$@"; do echo "$arg"; done arg1a arg1b arg2a arg2b arg3a arg3b $ for arg in "$*"; do echo "$arg"; done arg1a arg1b arg2a arg2b arg3a arg3b $ for arg in $@; do echo "$arg"; done arg1a arg1b arg2a arg2b arg3a arg3b $ for arg in $*; do echo "$arg"; done arg1a arg1b arg2a arg2b arg3a arg3b

This loops over the expansion, which in the first case "$@" is a separate parameter for each positional parameter, and in the second case "$*" a single string.

The third and fourth case, the unquoted ones, perform word splitting and are no different from each other.

See also the manual, "Special Parameters".

Collectives™ on Stack Overflow

Difference between $* and $@ in Bash [duplicate]

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related