Shell 1 Basics

Shell Introduction

The shell is a program written in C and a bridge for users to use Linux. The shell is both a command language and a programming language.
Shell script, a scripting program written for the shell.

Shell Environment

• The Bourne shell (/usr/bin/sh or/bin/sh) is the first shell used by UNIX and can be used on every UNIX
• Bourne Again Shell (/bin/bash) Linuxos default, he is the extension of the Bourne shell. is fully compatible with the Bourne shell and adds a lot of features to the Bourne shell. Functions such as command completion, command editing, and command history can be provided. It also contains many of the benefits of the C shell and Korn shell, with a flexible and powerful editing interface, and a friendly user interface.
• C Shell (/USR/BIN/CSH)
• K Shell (/usr/bin/ksh)

• Shell for Root (/sbin/sh)

  First shell script

#shell#test.sh#!/usr/bin/bash echo "Hello World!"

Hello world!

• #!/usr/bin/bash tells the system to use that shell to execute the script. *
• echo is used to output text to the window *

Execute shell Script

• Direct execution, no permissions required
  * * SH test.sh
  * * Source test.sh
• ./need to give executable permission
  chmod +x./test.sh need to give executable permissions
  ./test.sh use./Execute Script

Shell 1 Basics