In Linux grep stands for “global regular expression print”. The grep command used in searching and matching text files contained in the regular expressions. The syntax is: # grep pattern filename SNo Example Explanation 1 # grep apple filename The word apple will get extract from the filename 2 # grep -i apple filename ‘-i’ is a ignore case sensitive 3 # ls -l | grep filename List the files and in the listed files extract the filename 4 # ls -l | grep d Lists all the directories including files starting with d 5 # ls -l | grep ^d In this we will get only directories starting character of ‘d’ 6 # ls -l | grep ^- In this we will get only files