Integer Expression Expected : Bash

Question

I read on stack overflow that we need quotes here and added quotes, but it ddn't helped.

array_length=${fileNames[@]}

COUNTER=0

while [ "$COUNTER" -lt "$array_length" ]; do

I get the error still. Please help. Completely new to bash

Your mention of a previous question should be a link (you can edit the question and fix it, explained in the help) to help with context. But, just looking at the short piece you show, I see that you set a variable called array_length to a list of file names and then try to use it as a number. Unless fileNames has only one element (in which case you wouldn't be using [0]) and it happens to be a number, that invocation of test can't possibly work. — MAP
– MAP, Commented Jul 15, 2016 at 3:01
Sorry about that, I'll try to find it again. Didn't help me so I closed it. — Bhavya Arora
– Bhavya Arora, Commented Jul 15, 2016 at 3:03

mklement0 · Accepted Answer · 2016-07-15 03:39:45Z

6

array_length=${fileNames[@]}

should have been

array_length=${#fileNames[@]}

For the expected behaviour, your while loop should be:

while [ "$COUNTER" -lt "$array_length" ]
do
.
#do something
.
((COUNTER++)) # Equivalent to COUNTER=COUNTER+1
done

${fileNames[@]} expands to the whole array while prefixing it with # gives you the number of elements.

^Sidenotes:

^{1. Don't forget to increment COUNTER inside while loop.}
^{2. Try avoiding capitalized variables like COUNTER as they are usually reserved for the system.}

edited Jul 15, 2016 at 3:39

mklement0

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answered Jul 15, 2016 at 2:57

sjsam

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5 Comments

Bhavya Arora Over a year ago

Thanks, I'll accept it in 5 minutes. Can you also tell me what's wrong with this: "$COUNTER + 1" -lt "$array_length" This one still gives an error, if any major concept, I'll open a new question.

sjsam Over a year ago

@BhavyaArora : counter+1 will not increment counter.

Bhavya Arora Over a year ago

I don't want to increment it here, just want to compare it with the next number. How do I remove the error. And also what would increase the counter? let counter = counter + 1 ?

sjsam Over a year ago

@BhavyaArora : Not sure what you wisht exactly, See the edit.

sjsam Over a year ago

@mklement0 : Thankyou and as always,appreciated :)

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