The shell under Linux

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One of the shell versions used by Linux is the [Bourne Again Shell] abbreviated to bash. This shell is an enhanced version of the Bourne shell, developed under the GNU architecture.

The first popular Shell[bourne Shell]sh

Later the popular Shell C Shell is abbreviated CSH.

where C Shell wanted to be hot, because Linux was written in C, when many programmers used C to develop software.

Check the/etc/shells file for the shell that you can use under your Linux system. (Take my CentOS 6.5 example).

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

/bin/sh

/bin/bash

/sbin/nologin

/bin/dash

[Email protected] ~]#

and the bash shell is the default shell.

The/sbin/nologin inside can make it impossible for users to log on to the host with other services.

When you log in to Linux, the system gives a shell to let the lander work,

Check in/etc/paswd, System account bin, daemon, etc. use/sbin/nologin.

[Email protected] ~]# CAT/ETC/PASSWD

Root:x:0:0:root:/root:/bin/bash

Bin:x:1:1:bin:/bin:/sbin/nologin

Daemon:x:2:2:daemon:/sbin:/sbin/nologin

Adm:x:3:4:adm:/var/adm:/sbin/nologin

...

~/.bash_history records the commands that were run before the previous login.

The shell under Linux