Bash - array element exists

Question

I'm trying to see if first argument exists in an array:

#!/bin/bash

action="$1"
actions=( install run )
actionOK=false

for i in "${actions[@]}"
do
    if [ $i=$action ]; then
        actionOK=true
    fi
done

echo $actionOK

if [ $actionOK = false ]; then
    echo "unknown action: $action"
fi

now when trying wan27 run, the script echoes true, but it also echoes true for an action that is not in array, such as test, foo, bar or whatever

Answer 1

I think your script was working for "install", but not "run".

You need to do:

for i in "${actions[@]}"
do
  ...
done

This is because $actions expands to only the first element of the array.

$ array=( a b c )
$ echo $array
a
$ echo "${array[@]}"
a b c

See the bash arrays documentation for more details about how arrays work.

Any element of an array may be referenced using ${name[subscript]}. The braces are required to avoid conflicts with the shell's filename expansion operators. If the subscript is ‘@’ or ‘*’, the word expands to all members of the array name.

Answer 2

I tried the corrected script by François Vespa and it works for me ok, it outputs "unknown action: ..." if I pass something else than run or install.

The only error I see is when I don't pass any argument. You should check for [ $# -gt 0 ] or [ $# -eq 1 ] to find out if arguments were passed at all.