CODEWITHSUNDEEP
bash
Danny
Danny

Reputation: 45

Bash if statement is wrong

I have the following Bash code:

 while read -a line; do
    if [[ line[2] == $2 ]]; then
        version[n]=${line[1]}
        let n++
    fi
 done <"$file"

I know for a fact that there's a line in the file which is suppose to satisfy the if statement. I am not comparing numbers but strings so it's not the problem. What's the problem with my if statement?

Upvotes: 0

Views: 97

Answers (1)

Etan Reisner
Etan Reisner

Reputation: 81042

You need to use ${line[2]} there.

[[ doesn't automatically expand bare words like (( does.

See:

$ line=(a b c)
+ line=(a b c)
$ [[ line[1] = a ]]; echo $?
+ [[ line[1] = a ]]
+ echo 1
1
$ [[ ${line[1]} = a ]]; echo $?
+ [[ b = a ]]
+ echo 1
1
$ [[ ${line[0]} = a ]]; echo $?
+ [[ a = a ]]
+ echo 0
0
$ line=(0 1 2)
+ line=(0 1 2)
$ (( line[1] == 1 )); echo $?
+ ((  line[1] == 1  ))
+ echo 0
0
$ (( line[2] == 1 )); echo $?
+ ((  line[2] == 1  ))
+ echo 1
1

Note:

[[` does do bare word expansion when used with integer operations. However given how this actually works I don't like that behavior at all and do not understand why it works the way it does.

Upvotes: 5

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