grep.md

Unix

Grep

Grep is an acronym that stands for Global Regular Expression Print. The grep command consists of three parts in its most basic form. The first part starts with grep, followed by the pattern that you are searching for. After the string comes the file name that the grep searches through.

To Search a File

 grep access file.txt

Result:

u (user)	  + (add access)	     r (read)
g (group)	  - (remove access)	     w (write)
o (other)	  = (set exact access)	     x (execute)

Search All Files in Directory

grep access *

Result

file.txt: u (user)	  + (add access)	     r (read)
file.txt: g (group)	  - (remove access)	     w (write)
file.txt: o (other)	  = (set exact access)	     x (execute)
file2.txt:access is there in file2.txt
grep: folder: Is a directory
grep: new_folder: Is a directory
grep: p12: Is a directory
grep: permission: Is a directory

To Find Whole Words

grep -w access *

To Ignore Case in Grep Searches

grep  -i Access *

To Search Subdirectories

grep -r access *

To show Exactly Match

grep  -x "access is there in file2.txt" *

To List Names of Matching Files

grep -l access *

To Count number of matched

grep -c access *

To Limit grep Output

grep -m1  access *

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