bash script: how can we use nested if in a for loop

Question

#! /bin/bash

count=1
step=(a b)

for x in 0 1
do
    if [[ $count != '0' ]]; then
        if [[ ${step[x]} = "a"]]; then
            echo "Python test ($count)"
        else
            echo "stress test"
        fi
    fi
done

I get the following error

syntax error in conditional expression: unexpected token `;'
line 20: syntax error near `;
line 20: `        if [[ ${step[x]} = "a"]]; then'

Why?

How does line 9 get to be line 20?

ocodo
– ocodo

2011-02-02 22:15:57 +00:00
Commented Feb 2, 2011 at 22:15 — ocodo
– ocodo, Commented Feb 2, 2011 at 22:15

Walter Mundt · Accepted Answer · 2011-02-02 22:26:59Z

5

You need a space between "a" and the ]] in the second if.

More technically, [[ and ]] have to be separate tokens, and bash's parser doesn't separate tokens on quotes or most punctuation.

I believe your original code for the line is equivalent to if [[ ${step[x]} = "a]]"; then if that makes the issue more obvious.

edited Feb 2, 2011 at 22:26

answered Feb 2, 2011 at 22:08

Walter Mundt

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Comments

Eugene Yarmash · Accepted Answer · 2011-02-03 08:42:48Z

1

Change

if [[ ${step[x]} = "a"]]; then

to

if [[ ${step[$x]} = "a" ]]; then

i.e. ~~use $x instead of x and~~ add some space after the last parameter.

Update: You don't need to precede variables with a $ sign in array subscripts (also within double parenthesis (( )) or after the let keyword).

edited Feb 3, 2011 at 8:42

answered Feb 2, 2011 at 22:10

Eugene Yarmash

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4 Comments

ocodo Over a year ago

Yep, the x in array access is ok, but why?

user532648 Over a year ago

yeah it worked for me without the $, the issue was that i did not have a space after "a" ] .

user532648 Over a year ago

yeah it worked for me without the $, the issue was that i did not have a space after "a" ] . thanks

Dennis Williamson Over a year ago

@Slomojo: Array indices are an arithmetic context which doesn't require dollar signs. Similarly: ((a++)) and echo $((a * b))

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