What do $? $0 $1 $2 mean in shell script?

bash shell ash

Lin · Mar 25, 2015 · Viewed 281.2k times · Source

I often come across $? $0 $1 $2 etc.... in shell scripting, what I know is that $? returns the exit status of the last command

echo "this will return 0"
echo $?

but what do the others do? what are they called and is there more? perhaps like $3 $4 $5 ...

Answer

These are positional arguments of the script.

Executing

./script.sh Hello World

Will make

$0 = ./script.sh
$1 = Hello
$2 = World

Note

If you execute ./script.sh, $0 will give output ./script.sh but if you execute it with bash script.sh it will give output script.sh.