Linux Current Shell Summary!

Task handover, different systems, versions, and shells may not be the same. Some time ago to help a friend to engage in centos5.9, ya ya the use of incredibly is sh. It's crazy! Make a brief summary.

View the shell supported by the current system

[Email protected] ~]# Cat/etc/shells

/bin/sh

/bin/bash

/sbin/nologin

/bin/dash

[Email protected] ~]#

Note: You can install other shells yourself. Like Zsh.

View the shell that is currently in use by the system

1. Echo

I like to use the way, but This usage is not supported by all shells.

[Email protected] ~]# Echo

-bash

[Email protected] ~]#

2. Echo $SHELL

The most common command to view the shell, but not to reflect the current shell in real time. For example, you cannot display the child shell that is located.

[Email protected] ~]# echo $SHELL

/bin/bash

[[Email Protected]ode6 ~]#

3. Real-time view of the shell used in the current process

[[Email protected] ~]# PS | grep $$ | awk ' {print $4} '

Bash

[Email protected] ~]#

Or:ps-ef | grep $$ | Grep-v grep | Grep-v PS

(Note: $$ indicates the shell's process number)

4.

When you know the shell, you can view its version:

[Email protected] ~]# bash-version

GNU Bash, version 4.1.2 (1)-release (X86_64-REDHAT-LINUX-GNU)

Copyright (C) Software Foundation, Inc.

License gplv3+: GNU GPL version 3 or later

This was free software; Redistribute it.

There is NO WARRANTY, to the extent permitted by law.

[Email protected] ~]#

Special variables in the shell:

$

The name of the shell or shell script

$*

Give the argument list in pairs of double quotes

[Email protected]

Double quotation marks to return each parameter

$#

Number of parameters

$_

Represents the last parameter of the previous command

$$

PID that represents the command that is located

$!

PID that represents the last executed background command

$?

Represents the exit status after the execution of the previous command

--Ningzhiyuan Experience Summary

This article from the "[email protected]" blog, reproduced please contact the author!

Linux Current Shell Summary!