Tag: Shell
Variable description:
$
Shell PID (processid)
$!
PID of the background process last run by Shell
$?
End code of the last command (return value)
$-
Flag overview set by using the set command
$ *
List of all parameters. For example, when "$ *" is included in... $ N "to output all parameters.
[Email protected]
List of all parameters. For example, when "[email protected]" is enclosed "... All parameters are output in the form of "$ N.
$ #
Number of parameters added to Shell
$0
Shell file name
$1 ~ $ N
Parameters added to shell. $1 is the 1st parameter, and $2 is the 2nd parameter ....
Let's first write a simple script and then explain the meaning of each variable.
# Touch variable
# Vi variable
The script content is as follows:
#! /Bin/sh
Echo "number: $ #"
Echo "scname: $0"
Echo "First: $1"
Echo "Second: $2"
Echo "argume: [email protected]"
Save and exit
Grant the script execution permission
# Chmod + x variable
Execute scripts
#./Variable AA bb
Number: 2
Scname:./variable
First: AA
Second: bb
Argume: AA bb
The displayed result shows:
$ # Indicates the number of parameters passed to the script.
$0 is the script name.
$1 is the first parameter passed to the shell script.
$2 is the second parameter passed to the shell script.
[Email protected] is a list of all parameters passed to the script.
