Qfyilyi

I have a file called abc.txt with the contents as follows:

1: It is a shell script

2: There are few lines in this file

3: I am good with programming in C, but beginner in shell

4: We are going towards end of file

5: END OF FILE

I want to read each of the file iteratively, and in each iteration I want to compare the line with "I am good with programming in C, but beginner in shell", and then do some processing.

Any help would be greatly appreciated. Thanks!

Using a shell loop is unnecessary, as grep already iterates over lines:

grep '^[0-9]:  I am good with programming in C, but beginner in shell' input.txt

If there's a matching line, it will be printed. [0-9] defines range of characters that will be matched. We can also extend that to longer numbers [0-9]*: (and I think with perl regex -P option that could be done as [0-9]+:).

If a shell loop is really necessary, we can use case statement for pattern matching

while IFS= read -r line; do

    case $line in

        *": I am good with programming in C") echo "Matched: $line";;

    esac

done < input.xt

Try this sample code to help identify and modify to suit your needs:

#!/usr/bin/env bash

set -e

set -x 



cut -d" " -f2- "$1" | while IFS= read -r line

do

        if [ "$line" = "I am good with programming in C, but beginner in shell" ]

        then

                # Process things here

                echo "same"

        fi

done

Usage:

• 
  

  Make executable:

  
  
  

  chmod +x script.sh
  
  

  
  


• 
  

  Place script in any folder then run script by passing a file to it:

  
  
  

  ./script.sh /path/to/data.txt
  
  

  
  

Info:

• 
  cut -d" " -f2- "$1" |: Removes the leading line numbers and passes the results to the while loop.


• 
  IFS=: Option before read command to prevent leading/trailing whitespace from being trimmed.


• 
  -r: Option passed to read command prevents backslash escapes from being interpreted.


• 
  set -e: Bash option to stop script on first error.
  -set -x: Bash option used to debug the scrtip.


• 
  "$1": The file variable passed to the script in this case data.txt