Script execution mode

1、Shell What is it?

Shell It's a command line interpreter , It provides a way for users to Linux The kernel sends requests to run the program's interface system level program , Users can use Shell To start up , Hang up , Stop even writing some programs .

Shell It is also a powerful programming language , Easy to write , Easy to debug , More flexibility .Shell It's the script language that explains the execution , stay Shell You can call Linux System commands .

3、/etc/shells ----- Inquire about Linux Supported by Shell

1、echo The output command

#echo [ Options ] [ Output content ]

-e : Support character conversion of backslash control

\\ Output \ In itself

\a Output warning tone

\b backspace , That is to say, the left delete key

\c Cancel the line break at the end of the output line . and “-n” Consistent options

\e escape key

\f Page identifier 、

\n A newline

\r Enter key

\t tabs , That is to say Tab key

\v Vertical tabs

\0nnn According to octal ASCII Code table output characters . among 0 Is the number zero ,nnn It's a three digit octal number

\xhh In hexadecimal ASCII Code table output characters . among hh It's two hexadecimal numbers

give an example ：echo -e "\e[1;31m abcd\e[0m" ------ Representative to 31m Color output abcd.

2、 The first script

#vi hello.sh ( Find the specific text content in this machine ）

3、 Script execution

Grant execution permission , Direct operation

$chmod 755 hello.sh

$./hello.sh

adopt Bash Call the execution script

$Bash hello.sh