Shell Basics (top)

Shell Introduction

1. Other Shell:zsh,ksh

[[email protected] ~]# yum list | grep zshzsh.x86_64                                5.0.2-28.el7                 installedautojump-zsh.noarch                       22.3.0-3.el7                 epelzsh-html.x86_64                           5.0.2-28.el7                 basezsh-lovers.noarch                         0.9.0-1.el7                  epel[[email protected] ~]# yum list | grep kshksh.x86_64                                20120801-34.el7              basemksh.x86_64                               46-5.el7                     basepython-XStatic-Rickshaw.noarch            1.5.0.0-4.el7                epelpython-moksha-common.noarch               1.2.3-2.el7                  epelpython-moksha-hub.noarch                  1.5.3-2.el7                  epelpython-moksha-wsgi.noarch                 1.2.2-2.el7                  epel

Command history

1. Storage Address:

[[email protected] ~]# ls /root/.bash_history/root/.bash_history[[email protected] ~]# cat !$cat /root/.bash_historywhich lsecho $PATHwhereis lsyum installl -y locateyum installl -y mlocateyum install -y mlocatelocate

2. Store up to 1000 bars, controlled by scalar:

[[email protected] ~]# echo $HISTSIZE1000

3.HISTORY-C command:

清空内存里面命令历史，但是配置文件里面无法清空

4. When you exit the terminal, the memory saved history command will be written to the configuration file.
5. Modify the variable histsize:

[[email protected] ~]# vi /etc/profileHOSTNAME=`/usr/bin/hostname 2>/dev/null`HISTSIZE=1000if [ "$HISTCONTROL" = "ignorespace" ] ; then    export HISTCONTROL=ignoreboth

6. After the change is completed, the following command is required to take effect:

[[email protected] ~]# source /etc/profile

7. Let the saved history command have a specific time and date:
Temporary modification

[[email protected] ~]# HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S"[[email protected] ~]# echo $HISTTIMEFORMAT%Y/%m/%d %H:%M:%S[[email protected] ~]# history    1  2018/01/10 15:51:53history    2  2018/01/10 15:52:05cat .bash_history    3  2018/01/10 15:53:01history    4  2018/01/10 15:56:06vi /etc/profile    5  2018/01/10 15:57:46echo $HISTSIZE    6  2018/01/10 16:00:59HISTTIMEFORMAT=%Y%m%d %H:%M:%S    7  2018/01/10 16:01:29HISTTIMEFORMAT=%Y/%m/%d %H:%M:%S    8  2018/01/10 16:01:55HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S"    9  2018/01/10 16:02:13echo $HISTTIMEFORMAT   10  2018/01/10 16:02:19history

Permanently modified
Modifying profile profiles: Modifying variables to configuration files

vim /etc/profileHOSTNAME=`/usr/bin/hostname 2>/dev/null`HISTSIZE=1000HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S"[[email protected] ~]# echo $H

Then log back in to the terminal
8.!! Represents the previous command
9.! n indicates how many commands to run

  308  2018/01/10 17:21:54source /etc/profile  309  2018/01/10 17:27:01ls  310  2018/01/10 17:27:41history[[email protected] ~]# !309ls111  1.txt   2_hard.txt  2.txt.bak.bak  4.txt              apr-1.4.5123  1.txt~  2_soft.txt  3.txt          anaconda-ks.cfg.1  apr-1.4.5.tar.gz

10.! Command: In command history, look for the first command that starts with the command.

Command completion and aliases

1.CENTOS7 Support Command options: New packages need to be installed Bash-completion

[[email protected] ~]# yum install -y bash-completion已加载插件：fastestmirrorfile:///mnt/repodata/repomd.xml: [Errno 14] curl#37 - "Couldn‘t open file /mnt/repodata/repomd.xml"正在尝试其它镜像。Loading mirror speeds from cached hostfile正在解决依赖关系--> 正在检查事务---> 软件包 bash-completion.noarch.1.2.1-6.el7 将被 安装--> 解决依赖关系完成

Restart the system after installation reboot
2.alias aliases

[[email protected] ~]# alias restartnet=‘systemctl restart network.service‘        #建立别名[[email protected] ~]# restartnet

See what aliases are available

[[email protected] ~]# aliasalias cp=‘cp -i‘alias egrep=‘egrep --color=auto‘alias fgrep=‘fgrep --color=auto‘alias grep=‘grep --color=auto‘alias l.=‘ls -d .* --color=auto‘alias ll=‘ls -l --color=auto‘alias ls=‘ls --color=auto‘alias mv=‘mv -i‘alias restartnet=‘systemctl restart network.service‘alias rm=‘rm -i‘alias which=‘alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde‘

3. Place alias: In the following two places

[[email protected] ~]# vi .bashrc

[[email protected] ~]# cd /etc/profile.d

4. Alias: Unalias

[[email protected] ~]# unalias restartnet[[email protected] ~]# resreset       resize2fs   resizecons  resizepart  restorecon  [[email protected] ~]# resreset       resize2fs   resizecons  resizepart  restorecon  [[email protected] ~]# restartnet-bash: restartnet: 未找到命令

Wildcard, input and output redirection

*  表示任意数量任意字符

？代表任意一个字符

[1-3].txt      代表一个范围

{1,2}.txt         代表一个范围

>        把前一个命令的输出输入到后面文件中去，会把后面文件内容清空重写

>>          追加，不会删除后面文件内容

2>         把命令产生的错误信息输入到一个文件中去[[email protected] ~]# lsaaa 2> 2.txt[[email protected] ~]# cat 2.txt-bash: lsaaa: 未找到命令

2>>      错误追加重定向[[email protected] ~]# lsaaa 2>> 2.txt[[email protected] ~]# cat 2.txt-bash: lsaaa: 未找到命令-bash: lsaaa: 未找到命令

&>          把错误和正确信息都输入到一个文件[[email protected] ~]# ls [12].txt aaa.txt &>a.txt[[email protected] ~]# cat a.txtls: 无法访问aaa.txt: 没有那个文件或目录2.txt

&>>       把错误和正确信息都追加到一个文件

可以把正确和错误的分开存放[[email protected] ~]# ls [12].txt aaa.txt >1.txt 2>a.txt[[email protected] ~]# cat 1.txt2.txt[[email protected] ~]# cat a.txtls: 无法访问aaa.txt: 没有那个文件或目录

<        输入重定向[[email protected] ~]# wc -l 2.txt > 1.txt[[email protected] ~]# cat 1.txt2 2.txt[[email protected] ~]# wc -l < 1.txt1[[email protected] ~]# wc -l 1.txt1 1.txt

Shell Basics (top)