Author: Sandeep Sadanandan

Use to get input (data from user) from keyboard and store (data) to variable. Syntax:  read variable1, variable2,…variableN   eg: #!/bin/sh echo “Enter your name please” read fname echo “Welcome $fname”

By default in Linux if particular command/shell script is executed, it return two type of values which is used to see whether command or shell script executed is successful or not. (1) If return value is zero (0), command is successful. (2) If return value is nonzero, command is not successful or some sort of error executing command/shell […]

Mainly three types of quotes are used. 1. ” – Double quotes: Anything enclose in double quotes removed meaning of that characters (except and $). 2. ‘ – Single quotes: Enclosed in single quotes remains unchanged. 3. ` – Back quotes: To execute command    

used to perform arithmetic operations in shell scripts. Synatax: $ expr  op1 operator  op2 eg: $ expr 1 + 3 $ expr 2 – 1 $ expr 10 / 2 $ expr 20 % 3 $ expr 10 * 3 $ echo `expr 6 + 3` in the last one we used back quote (` […]

Redirection is a function common to most command-line interpreters, including various unix shells that can redirect standard streams to user specified locations. UNIX STANDARD I/O Streams 0- stdin (Standard input) 1- stdout (Standard output) 2- stderr (standard error)       Redirecting standard input and standard output simple redirection to a file:  $command  > file […]