Weird Bash error while comparing a string and a variable

Question

So I am pretty familiar with bash but the second if statement keeps throwing me an error.

./run.sh: line 39: [: q: integer expression expected
./run.sh: line 39: [: q: integer expression expected

I am not exactly sure what is the problem. I am pretty sure my syntax is correct.

read -p "Option Number-> " answer
#  Check to see if the answer is only letters
if [[ "$answer" =~ ^[a-zA-Z]+$ ]];then
    if [ "$answer" -eq "q" ] || [ "$answer" -eq "Q" ];then
        exit
    fi

Add a shebang and then paste your script there: http://www.shellcheck.net/ — Cyrus, Feb 04 '19 at 22:52
[How can I compare a variable to a text string, rather than integer, in an if/else statement?](https://superuser.com/q/543793/173513), [Bash - Integer expression expected](https://unix.stackexchange.com/q/293495/56041), [Bash: Integer expression expected](https://stackoverflow.com/q/17958855/608639), etc. — jww, Feb 05 '19 at 04:03

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

3

-eq is used for integer comparisons, for text comparisons use =

From the bash man pages:

arg1 OP arg2

          OP  is one of -eq, -ne, -lt, -le, -gt, or -ge.  These arithmetic
          binary operators return true if arg1 is equal to, not equal  to,
          less  than, less than or equal to, greater than, or greater than
          or equal to arg2, respectively.  Arg1 and arg2 may  be  positive
          or negative integers.

and

string1 == string2

string1 = string2

          True if the strings are equal.  = should be used with  the  test
          command  for  POSIX conformance.  When used with the [[ command,
          this performs pattern matching as described above (Compound Com-
          mands).

By the way, your comparison could be written as a pattern:

if [[ "$answer" == [Qq] ]]

edited Jun 20 '20 at 09:12

Community

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answered Feb 04 '19 at 22:48

cdarke

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There must be dozens of duplicates for this. Although I'm not sure how to search for them. – Barmar Feb 04 '19 at 22:54
@Barmar: probably, but it's quicker to answer it. – cdarke Feb 04 '19 at 22:55
Well, this is a nice, succinct answer, I'll make it my dupe candidate. – Barmar Feb 04 '19 at 22:56
@Barmar I only found lots of questions with that error message that are *almost* duplicates, but no good one. – Benjamin W. Feb 04 '19 at 22:57
However, I don't think "quicker to answer" is a good reason to answer duplicates. – Benjamin W. Feb 04 '19 at 22:58
You're the best – j jones Feb 04 '19 at 23:36
And yes trust me I am not trying to create duplicates. I know it was a stupid syntax error but I was stuck on it for an hour and bash errors are so vague that nothing helpful comes up on google. – j jones Feb 04 '19 at 23:37
@jjones: sympathies. The problem with searching for duplicates is that you often need to know the answer to do the right search! – cdarke Feb 05 '19 at 10:37

Weird Bash error while comparing a string and a variable

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