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 FILEI 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!
2 Answers
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.txtIf 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: $line";; esac
done < input.xtTry this sample code to help identify and modify to suit your needs:
#!/usr/bin/env bash
set -e
set -x
while read -r linenum line
do if [ "$line" = "I am good with programming in C, but beginner in shell" ] then # Process things here echo "same" fi
done < "$1"Usage:
Make executable:
chmod +x script.shPlace script in any folder then run script by passing a file to it:
./script.sh /path/to/data.txt
Info:
-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 casedata.txtlinenum: variable that holds the line numbers when bash splits the read lines into two variables while the other is passed in via thelinvariable.
