Bash script to check if string1 contains string2

Sebbern · 12-13-2009, 10:37 AM

Help!

I'm going to make a bash script that checks if string1 contains string2.

So far i've got:

Code:

#!/bin/bash

input=$(echo $@)
if [ input == .txt ]
then
echo "yes"
else
echo "no"
fi

But that dosen't work!

Please help

colucix · 12-13-2009, 10:47 AM

Some notes about your script:

1) you don't really need the assignment

Code:

input=$(echo $@)

since you can use $@ directly in the expression inside the if/then construct.

2) you forgot to put a $ sign before the variable name inside the expression:

Code:

if [ $input == .txt ]

without that you just evaluate the equivalence between two strings, which is obviously always false.

3) if using bash version 3 you can try the operator for Regular Expression Match so that your script will look like

Code:

#!/bin/bash
if [[ $@ =~ [.]txt ]]
then
  echo yes
else
  echo no
fi

ghostdog74 · 12-13-2009, 08:21 PM

you can use case/esac

Code:

string1="abcdef"
string2="abc"
case "$string1" in
    *$string2* )
        echo "found"
        ;;
    *) echo "not found"
esac

bsat · 12-14-2009, 01:05 AM

awk implementation of the same.
BEGIN {
string1="abcdef"
string2="abcd"
if(match(string1,string2))
{
print "found"
}
else
{
print "not found"
}
}

ghostdog74 · 12-14-2009, 01:38 AM

you should put your code in code tags.
Or this as well:

Code:

BEGIN {
  string1="abcdef"
  string2="abcd"
  if( string1 ~ string2){
      print "found"
  }else{
      print "not found"
  }
}

bsat · 12-15-2009, 05:19 AM

oh, ok I will do that in future . thanks for the info ghostdog :-)