Common commands for Linux ""

Cat: View or merge file contents

Example: View 1.txt and 2.txt file content and merge 1.txt and 2.txt file content into 3.txt

grep: Text Search {format: gerp [-options] ' search content string ' filename }

The grep command is a powerful text Search tool that grep allows for pattern lookups on text files . If a matching pattern is found, grep prints all rows that contain the pattern.

1. grep Common options:

Options	Meaning
-V	Display all lines that do not contain matching text (equivalent negation)
-N	Display matching lines and line numbers
-I.	Ignore case

2. grep Common Regular Expressions:

Find : File Lookup {format: find directory-name file name }

Typically used to search for a qualifying file in a specific  directory  , or to search for a specific user's owner's file

Common usage:

Command	Meaning
Find./-name test.sh	Find all files named test.sh in the current directory
Find./-name ' *.sh '	Find all files with the suffix. Sh in the current directory
Find./-name "[a-z]*"	Find all files in the current directory that begin with uppercase letters
Find/tmp-size 2M	Find files that are equal to 2M in the/tmp directory
Find/tmp-size +2m	Find files larger than 2M in the/tmp directory
Find/tmp-size-2m	Find files less than 2M in the/tmp directory
Find./-size +4k-size-5m	Find files larger than 4k and less than 5M in the current directory
Find./-perm 0777	Find a file or directory with permission 777 under the current directory

WC: Calculates the number of lines or words of a file

Common commands for Linux ""