Bash array ignores if conditions given

Question

I'm reading a file like

state 100 NULL
operator 2 0 3 NULL

and I want to parse it to an array line wise to check it for certain conditions so what i actual do is:

#!/bin/bash
fileLines=$(cat file)
IFS=$'\n'
for line in $fileLines
do
    IFS=$' ' read -r -a lineArray <<< $line 
    echo ${lineArray[@]}
    if [[ ${lineArray["state"]} ]] ; 
    then
       echo "hit"
    fi
done

but it unfortunately comes back with the output

state 100 NULL
hit
operator 2 0 3 NULL
hit

even if I check for equality by using

if [[ ${lineArray[0]} == "state" ]] ;

it is still ignoring the condition I gave to the script. Is there a better way to check my array for conditions?

@doubleDown your right. Seems that I made a mistake on this statement earlier. But the original code is not working. In fact, that i have to add some more conditions i prefer the code of fedorqui, it's very good readable. — BlueSapphire
– BlueSapphire, Commented Jun 20, 2013 at 12:29

fedorqui · Accepted Answer · 2013-06-20 11:43:31Z

1

Why don't you check it like this?

[[ "$line" == *"stat"*  ]] && echo yes

Test

$ t="operator 2 0 3 NULL"
$ [[ "$t" == *"stat"*  ]] && echo yes
$

$ t="stat 100 NULL"
$ [[ "$t" == *"stat"*  ]] && echo yes
yes

answered Jun 20, 2013 at 11:43

fedorqui

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4 Comments

chepner Over a year ago

To go along with this answer, you don't need to read the entire file into memory at once; just read it line-by-line: while read -r line; do ...; done < file.

fedorqui Over a year ago

So the -r makes it load just one line each time instead of the entire file?

chepner Over a year ago

read always just reads one line; the -r simply tells read not to process backslashes in the input specially.

fedorqui Over a year ago

Ah, right, so your proposal is to use while read instead of the for line in in the OP. Good one.

l0b0 · Accepted Answer · 2013-06-20 11:52:49Z

1

The array is indexed by integers, and it looks like any non-integer strings are coerced to zero, so ${lineArray["state"]} will always return ${lineArray[0]}. man bash is rather vague on the subject:

Referencing an array variable without a subscript is equivalent to referencing the array with a subscript of 0.

Based on the last line of code you posted, it's unclear what you actually are trying to accomplish with this code.

edited Jun 20, 2013 at 11:52

answered Jun 20, 2013 at 11:45

l0b0

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