CODEWITHSUNDEEP
bash
machinery
machinery

Reputation: 6290

Bash checking if string does not contain other string

I have a string ${testmystring} in my .sh script and I want to check if this string does not contain another string.

    if [[ ${testmystring} doesNotContain *"c0"* ]];then
        # testmystring does not contain c0
    fi

How can I do that, i.e. what is doesNotContain supposed to be?

Upvotes: 113

Views: 214220

Answers (3)

Thiago Conrado
Thiago Conrado

Reputation: 853

Bash allow u to use =~ to test if the substring is contained. Ergo, the use of negate will allow to test the opposite.

fullstring="123asdf123"
substringA=asdf
substringB=gdsaf
# test for contains asdf, gdsaf and for NOT CONTAINS gdsaf 
[[ $fullstring =~ $substring ]] && echo "found substring $substring in $fullstring"
[[ $fullstring =~ $substringB ]] && echo "found substring $substringB in $fullstring" || echo "failed to find"
[[ ! $fullstring =~ $substringB ]] && echo "did not find substring $substringB in $fullstring"

Upvotes: 24

Roberto De Oliveira
Roberto De Oliveira

Reputation: 129

As mainframer said, you can use grep, but i would use exit status for testing, try this:

#!/bin/bash
# Test if anotherstring is contained in teststring
teststring="put you string here"
anotherstring="string"

echo ${teststring} | grep --quiet "${anotherstring}"
# Exit status 0 means anotherstring was found
# Exit status 1 means anotherstring was not found

if [ $? = 1 ]
then
  echo "$anotherstring was not found"
fi

Upvotes: 8

cychoi
cychoi

Reputation: 3090

Use !=. 

if [[ ${testmystring} != *"c0"* ]];then
    # testmystring does not contain c0
fi

See help [[ for more information.

Upvotes: 185

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