Linux Shell Script - String Comparison with wildcards

Question

I am trying to see if a string is part of another string in shell script (#!bin/sh).

The code i have now is:

#!/bin/sh
#Test scriptje to test string comparison!

testFoo () {
        t1=$1
        t2=$2
        echo "t1: $t1 t2: $t2"
        if [ $t1 == "*$t2*" ]; then
                echo "$t1 and $t2 are equal"
        fi
}

testFoo "bla1" "bla"

The result I'm looking for, is that I want to know when "bla" exists in "bla1".

Thanks and kind regards,

UPDATE: I've tried both the "contains" function as described here: How do you tell if a string contains another string in Unix shell scripting?

As well as the syntax in String contains in bash

However, they seem to be non compatible with normal shell script (bin/sh)...

Help?

check this stackoverflow.com/questions/229551/string-contains-in-bash — YTech
– YTech, Commented Nov 10, 2013 at 15:56
Same question and answered here: stackoverflow.com/questions/229551/string-contains-in-bash stackoverflow.com/questions/2829613/… — n2studio
– n2studio, Commented Nov 10, 2013 at 15:57

Mr. Llama · Accepted Answer · 2021-09-05 20:12:32Z

82

When using == or != in bash you can write:

if [[ $t1 == *"$t2"* ]]; then
    echo "$t1 and $t2 are equal"
fi

Note that the asterisks go on the outside of the quotes and that the wildcard pattern must be on the right.

For /bin/sh, the = operator is for equality only, not pattern matching. You can use case for pattern matching though:

case "$t1" in
    *"$t2"*) echo t1 contains t2 ;;
    *) echo t1 does not contain t2 ;;
esac

If you're specifically targeting Linux, I would assume the presence of /bin/bash.

edited Sep 5, 2021 at 20:12

Mr. Llama

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answered Nov 11, 2013 at 0:37

glenn jackman

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9 Comments

AlexT82 Over a year ago

Thanks a bunch Glenn! very much appreciated! (and it's a linux environment, but very lightweight, and without /bin/bash so i really needed that /bin/sh version! - thanks again!)

lef Over a year ago

Better than coping with case, use =~ operator: if [[ $t1 =~ %t2* ]]; the echo match; fi

glenn jackman Over a year ago

@lef, for a regular expression, you want [[ $t1 =~ "$t2" ]]

lef Over a year ago

@glenn, right, besides a typo (%t2 instead of $t2), sh actually may not support double brackets [[ ]]

barakbd Over a year ago

Notice that order matters: the wilds cards need to be on the right hand side of the comparison... at least from my experience.

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