SUMMARY shell
shell is a command line interpreter, which provides a transmission request to the kernel to run the program for the user interface system level program, the user can start with a shell, suspend, stop or even some programs are written.
shell is still a quite powerful programming language, easy to write, easy to debug, flexibility is strong. shell scripting language is interpreted, in the shell can call the Linux system commands directly
Classification of the shell
Bourne Shell: From 1979 onwards began using Unix Bourne Shell, Bourne Shell master file called SH
C Shell: Shell C is mainly used in the BSD version of Unix systems, and its syntax is similar to c language named
Shel there are two main types of grammar Bourne and C, both of grammar is not compatible with each other. Bourne family including sh, ksh, Bash, psh, zsh; C family including: csh, tcsh
Bash: sh compatible with Bash, Linux is now used as a basic Bash Shell using the user's
Supported Linux shell
/ etc / shells
shell script execution mode
echo command output
echo [options] [output] content
-e: Support backslash character conversion control
-e echo "ab & \ BC"
# delete the character to the left
echo -e "A \ TB \ TC \ Nd \ TE \ TF"
# newline and tab
echo -e "\ e [1; 31m abcd \ e [ 0m "
# output color
# 30m = black, 31m = red, 32m = green, 33m = yellow
# 34m = blue, 35m = magenta, 36m = cyan, 37m = white
The first script
vi hello.sh
#! / Bin / Bash
echo -e "hanzhiyu ahhahahah"
Script execution
given execute permissions, directly run
chmod 755 hello.sh
./hello.sh
execute the script by calling Bash
Bash hello.sh