When you’re searching for a text in a particular file under a Linux system you’re usually using the grep command. grep stands for Get Regular Expression and Print, in this article we’ll show several examples of how to use it:
Using grep for a basic search
grep "textToSearchFor" file.txt
grep for a case-insensitive search
grep -i "THIS CASING DOESN'T MATTER" file.conf
grep without matching
grep -v "thisWillNotBeMatched" file.txt
grep for word matching
Usually, grep searches like how you would match a Regular Expression (as it’s in its name), if you would like to apply \b search you would use
grep -w "justThisWordWillBeMatched" file.cnf
grep for to count the number of occurrences
grep -c "howManyTimesThisAppearsInTheFile" file.php
grep with line numbers
This will show the number of the line the match is found
grep -n "whichLineIsThisOn" file.txt
