Compare variable with integer in shell?

Question

I have an if statement I need to run, as long as the value I have stored in my $counter variable is greater than 5.

Here is the respective section of my current (non-functioning) script:

if $counter > 5
then
    echo "something"
fi

The mistake I'm making is probably very obvious, but for some reason I couldn't find the solution online.. Thanks!

score 49 · Accepted Answer · answered Aug 08 '13 at 18:18

49

Well that is quite simple:

if [ "$counter" -gt 5 ]
then
    echo "something"
fi

answered Aug 08 '13 at 18:18

konsolebox

2

Unless you need `sh` compatibility, it's better to use `[[` and `]]` instead of `[` and `]`. See http://mywiki.wooledge.org/BashFAQ/031 – Thomas Aug 08 '13 at 18:20
Of course. It's meant for compatibility seeing that he didn't mention bash in the title. – konsolebox Aug 08 '13 at 18:23
@konsolebox, you need to look at the tags below the question. Titles are very often misleading. – glenn jackman Aug 08 '13 at 18:44
@glennjackman yeah i just noticed the tags :) – konsolebox Aug 08 '13 at 18:48
2

If you're using `bash`, `(( counter > 5 ))` is even better. – chepner Aug 08 '13 at 20:05
@chepner I disagree: http://stackoverflow.com/a/18568726/445221 – konsolebox Nov 05 '15 at 19:23
1

@glennjackman I'm actually not sure if everyone who tags `bash` knows the difference between `bash` and simply `sh`. (Commenting for reference). – konsolebox Nov 05 '15 at 19:25
Upvoting this in 2021 exactly because I was looking for a portable syntax. – ob-ivan Aug 19 '21 at 09:06

score 26 · Answer 2 · answered Aug 08 '13 at 18:18

26

Arithmetic needs to be done between (( and )):

if (( $counter > 5 ))

Incidentally, you can also leave off the $ in arithmetic, though it doesn't hurt to keep it.

answered Aug 08 '13 at 18:18

Thomas

Yes however, I would argue conditional expressions should be done in `[[ ]]`. So which one should really be it? I'd pick `[[ ]]`. See my arguments here: http://stackoverflow.com/a/18568726/445221. (Commenting for reference). – konsolebox Nov 05 '15 at 19:25

2 Answers2