How do I negate two logic tests with regular expressions in a bash script?

Question

In bash, we would like to do the following logic: if the variable "$SLACK" is TRUE and ${OUTPUT} is not equal to "mysql: [Warning] Using a password on the command line interface can be insecure", call the slack_it function.

I have tried more than a dozen solutions provided from the posts here How do I negate a test with regular expressions in a bash script?, Check if a string matches a regex in Bash script, but none of them work. Could any guru enlighten?

#!/bin/bash

if [ "$SLACK" == "TRUE" ]
   then
        if ! [[ ${OUTPUT} =~ "*mysql: [Warning] Using a password on the command line interface can be insecure*" ]]
            then
                slack_it
        fi
  fi

I am curious why you are set on using a regular expression. It sounds like you got it to work without a regular expression. Why complicate things? Or is this a mind exercise? — Bill Rosmus, Apr 24 '17 at 23:07

wjandrea · Accepted Answer · 2017-04-24T23:04:05.030

3

The stars need to be outside the quotes.

Also, the =~ operator is for regex, == for globs.

So:

if ! [[ ${OUTPUT} == *"mysql: [Warning] Using a password on the command line interface can be insecure"* ]]; then
    slack_it
fi

edited Apr 24 '17 at 23:04

answered Apr 24 '17 at 23:02

wjandrea

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codeforester · Answer 2 · 2017-04-24T23:00:10.393

1

Your issue seems to be related to the leading and trailing *. Try:

if ! [[ ${OUTPUT} =~ "mysql: [Warning] Using a password on the command line interface can be insecure" ]]; then
  slack_it
fi

edited Apr 24 '17 at 23:00

answered Apr 24 '17 at 22:54

codeforester

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1

You also [can't use quotes when matching regular expressions in Bash](http://stackoverflow.com/q/218156/1426891), or it'll force string matching. Saving the regex to a variable seems to be the workaround of choice. – Jeff Bowman Apr 24 '17 at 22:56

How do I negate two logic tests with regular expressions in a bash script?

2 Answers2