8.1 sehll 介绍
什么是shell
shell 是一个命令解释器，提供用户和机器之间交互
支持特定的语法，比如逻辑判断，循环.
每个用户都可以有自己特定的shell.
centos7 默认的shell 为bash( Bourne Agin shell )
还有zsh ,ksh等
8.2 命令历史
/root/.bash_history ;命令历史放置文件
[[email protected] ~]# ls /root/.bash_history/root/.bash_history [[email protected] ~]# cat !$cat /root/.bash_history
history ;查看系统存储的命令,最多可以存储1000条
[[email protected] ~]# history | tail 995 make install 996 echo $? 997 ls /usr/local/apache2 998 init 0 999 ls /root/.bash_history 1000 cat $! 1001 ls /root/.bash_history 1002 cat /root/.bash_history 1003 history 1004 history | tail [[email protected] ~]#
可以看到有1004 条，是因为还没有写入到文件中，暂时存在于内存中
echo $HISTSIZE ; 查看变量的值
[[email protected] ~]# echo $HISTSIZE1000[[email protected] ~]#
history -c ; 清空内存中的历史命令，并不会清空 /root/.bash_history 中保存的命令
[[email protected] ~]# history -c[[email protected] ~]# history 8 history [[email protected] ~]# cat .bash_history | tailcd ..lscd httpd-2.2.32 lsmakeecho $?make installecho $?ls /usr/local/apache2 init 0[[email protected] ~]#
当退出当前终端时，内存中保存的命令会保存到 /root/.bash_history 文件中去
vim /etc/profile ; 在配置文件中修改 HISTTORY 变量的值
[[email protected] ~]# vim /etc/profileHOSTNAME=`/usr/bin/hostname 2>/dev/null` HISTSIZE=2000if [ "$HISTCONTROL" = "ignorespace" ] ; then export HISTCONTROL=ignoreboth
source /etc/profile ； 重新加载文件之后，HISTSIZE 变量的值在会改变
[[email protected] ~]# echo $HISTSIZE1000[[email protected] ~]# source /etc/profile[[email protected] ~]# echo $HISTSIZE2000[[email protected] ~]#
HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " ; 设置命令历史显示格式
[[email protected] ~]# HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " [[email protected] ~]# echo $HISTTIMEFORMAT%Y/%m/%d %H:%M:%S [[email protected] ~]# history 8 2017/06/25 12:27:07 history 9 2017/06/25 12:31:05 cat .bash_history 10 2017/06/25 12:31:14 cat .bash_history | tail 11 2017/06/25 12:35:08 cat /etc/profile 12 2017/06/25 13:10:00 vim /etc/profile 13 2017/06/25 13:14:38 echo $HISTORY 14 2017/06/25 13:15:34 echo $HISTTORY 15 2017/06/25 13:16:10 echo $HISTSIZE 16 2017/06/25 13:16:47 source /etc/profile 17 2017/06/25 13:17:13 echo $HISTSIZE 18 2017/06/25 13:19:55 history 19 2017/06/25 13:25:16 HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " 20 2017/06/25 13:25:37 echo $HISTTIMEFORMAT 21 2017/06/25 13:25:49 history [[email protected] ~]#
只在当前终端生效，如果要在别的中终端生效，需要将变量加入到/etc/profile中
[[email protected] ~]# vim /etc/profileHISTSIZE=2000HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S "[[email protected] ~]# source /etc/profile
chattr +a /root/.bash_history ； 给文件设置 a 权限，防止被删除
[[email protected] ~]# chattr +a /root/.bash_history[[email protected] ~]# lsattr /root/.bash_history-----a---------- /root/.bash_history [[email protected] ~]#
!! 表示执行上一条命令，也就是命令历史中的最后一条命令
[[email protected] ~]# ls111.txt 1.txt 1.txt.1 2.txt 3.txt anaconda-ks.cfg httpd-2.2.32.tar.gz [[email protected] ~]# !!ls111.txt 1.txt 1.txt.1 2.txt 3.txt anaconda-ks.cfg httpd-2.2.32.tar.gz [[email protected] ~]# w 13:43:44 up 5:12, 2 users, load average: 0.00, 0.01, 0.05USER TTY FROM [email protected] IDLE JCPU PCPU WHAT root pts/0 192.168.86.1 08:32 8.00s 0.21s 0.06s w root pts/1 192.168.86.1 13:33 9:04 0.03s 0.03s -bash [[email protected] ~]# !!w 13:43:46 up 5:12, 2 users, load average: 0.00, 0.01, 0.05USER TTY FROM [email protected] IDLE JCPU PCPU WHAT root pts/0 192.168.86.1 08:32 2.00s 0.16s 0.01s w root pts/1 192.168.86.1 13:33 9:06 0.03s 0.03s -bash [[email protected] ~]#
!n ;表示执行命令历史里的第n条命令，n 表示第几条命令
[[email protected] ~]# history 8 2017/06/25 12:27:07 history 9 2017/06/25 12:31:05 cat .bash_history 10 2017/06/25 12:31:14 cat .bash_history | tail 11 2017/06/25 12:35:08 cat /etc/profile 12 2017/06/25 13:10:00 vim /etc/profile 13 2017/06/25 13:14:38 echo $HISTORY 14 2017/06/25 13:15:34 echo $HISTTORY 15 2017/06/25 13:16:10 echo $HISTSIZE 16 2017/06/25 13:16:47 source /etc/profile 17 2017/06/25 13:17:13 echo $HISTSIZE 18 2017/06/25 13:19:55 history 19 2017/06/25 13:25:16 HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " 20 2017/06/25 13:25:37 echo $HISTTIMEFORMAT 21 2017/06/25 13:25:49 history 22 2017/06/25 13:31:12 vim /etc/profile 23 2017/06/25 13:33:21 source /etc/profile 24 2017/06/25 13:39:08 chattr +a /root/.bash_history 25 2017/06/25 13:39:38 lsattr /root/.bash_history 26 2017/06/25 13:43:18 ls 27 2017/06/25 13:43:40 W 28 2017/06/25 13:43:43 w 29 2017/06/25 13:45:46 history [[email protected] ~]# !17echo $HISTSIZE2000[[email protected] ~]#
!+字符串 ；表示执行以字符串开头的，history中最近的一条命令
[[email protected] ~]# history | tail -n 7 29 2017/06/25 13:45:46 history 30 2017/06/25 13:46:00 echo $HISTSIZE 31 2017/06/25 13:50:11 w 32 2017/06/25 13:53:03 history | tail 33 2017/06/25 13:53:18 history | tail -n 3 34 2017/06/25 13:53:32 history | tail -n3 35 2017/06/25 13:53:47 history | tail -n 7[[email protected] ~]# [[email protected] ~]# !echoecho $HISTSIZE2000[[email protected] ~]# !ww 13:50:11 up 5:19, 2 users, load average: 0.00, 0.01, 0.05USER TTY FROM [email protected] IDLE JCPU PCPU WHAT root pts/0 192.168.86.1 08:32 3.00s 0.17s 0.01s w root pts/1 192.168.86.1 13:33 15:31 0.03s 0.03s -bash [[email protected] ~]#
8.3 命令补全与别名
tab 键命令补全
- 敲一下 补全命令或路径
- 敲两下 列出当前目录下的所有文件
yum install -y bash-completion ；安装包之后tab键可以补全命令的参数
- 安装完之后需要重新启动系统，才能生效
[[email protected] ~]# rpm -q bash-completionbash-completion-2.1-6.el7.noarch [[email protected] ~]# systemctl restart network
alias restartnet=‘systemctl restart network.service‘ ; 设置别名
[[email protected] ~]# alias restartnet=‘systemctl restart network.service‘[[email protected] ~]# restartnet[[email protected] ~]#
alias ; 列出系统所有的别名
[[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‘[[email protected] ~]#
/root/.bashrc /etc/profile.d ; 定义alias 的文件
- /root/.bashrc
[[email protected] ~]# cat /root/.bashrc# .bashrc# User specific aliases and functionsalias rm=‘rm -i‘alias cp=‘cp -i‘alias mv=‘mv -i‘# Source global definitionsif [ -f /etc/bashrc ]; then . /etc/bashrc fi [[email protected] ~]#
- /etc/profile.d 下的脚本文件中
[[email protected] ~]# ls /etc/profile.d256term.csh colorgrep.csh colorls.sh less.csh vim.sh256term.sh colorgrep.sh lang.csh less.sh which2.csh bash_completion.sh colorls.csh lang.sh vim.csh which2.sh
unalias restartnet ; 取消自定义的别名
[[email protected] ~]# unalias restartnet[[email protected] ~]# restartnet-bash: restartnet: 未找到命令 [[email protected] ~]#
8.4 通配符
* 任意个任意字符
[[email protected] ~]# ls *.txt111.txt 1.txt 2.txt 3.txt [[email protected] ~]# ls *txt*111.txt 1.txt 1.txt.1 2.txt 3.txt [[email protected] ~]# ls 1*111.txt 1.txt 1.txt.1[[email protected] ~]#
? ;表示一个任意字符
[[email protected] ~]# ls ?.txt1.txt 2.txt 3.txt [[email protected] ~]#
ls [1-9].txt ； 列出包含数字的文件 [0-9],[123],[23],[a-z],[A-Z],[0-9a-zA-Z]
[[email protected] ~]# ls [0-9].txt1.txt 2.txt 3.txt [[email protected] ~]# le [23].txt-bash: le: 未找到命令 [[email protected] ~]# ls [23].txt2.txt 3.txt [[email protected] ~]#
ls {1,2,3}.txt ; 列出包含花括号当中的文件
[[email protected] ~]# ls {1,2}.txt1.txt 2.txt
[[email protected] ~]# ls {1,2,3}.txt1.txt 2.txt 3.txt
[[email protected] ~]#
8.5 输入输出重定向
cat 1.txt > 2.txt ;重定向，将前一个命令的结果重定向到后面的文件中
[[email protected] ~]# cat 2.txt1234567890[[email protected] ~]# cat 1.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]# cat 1.txt > 2.txt[[email protected] ~]# cat 2.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]#
cat 1.txt >> 2.txt ; 追加重定向，将前面命令的输出追加到后面的文件中
[[email protected] ~]# cat 1.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]# cat 2.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]# cat 1.txt >> 2.txt[[email protected] ~]# cat 2.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologinchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]#
lsaa 2> a.txt ; 错误重定向
[[email protected] ~]# touch a.txt[[email protected] ~]# lsaaa -bash: lsaaa: 未找到命令 [[email protected] ~]# lsaaa 2> a.txt[[email protected] ~]# cat a.txt-bash: lsaaa: 未找到命令 [[email protected] ~]#
lsaa 2>> a.txt ; 追加错误重定向
[[email protected] ~]# cat a.txt-bash: lsaaa: 未找到命令 [[email protected] ~]# lsaaa 2>> a.txt[[email protected] ~]# lsaaa 2>> a.txt[[email protected] ~]# cat a.txt-bash: lsaaa: 未找到命令 -bash: lsaaa: 未找到命令 -bash: lsaaa: 未找到命令 [[email protected] ~]#
ls [23].txt aaa.txt &> a.txt ; &> 相当于 2> + >
[[email protected] ~]# ls [23].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.txt3.txt[[email protected] ~]#
ls [23].txt aaa.txt &>> a.txt ; &>> 相当于 2>> + >>
[[email protected] ~]# ls [23].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.txt3.txtls: 无法访问aaa.txt: 没有那个文件或目录 2.txt3.txt[[email protected] ~]#
ls [23].txt aaa.txt > 1.txt 2> a.txt ; 将正确输出和错误输出到不同的文件中
[[email protected] ~]# ls [23].txt aaa.txt > 1.txt 2> a.txt[[email protected] ~]# cat 1.txt2.txt3.txt [[email protected] ~]# cat a.txtls: 无法访问aaa.txt: 没有那个文件或目录 [[email protected] ~]#
wc -l <2.txt ; 输入重定向，左边一定是一个命令，不能是文件
[[email protected] ~]# cat 2.txtchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologinchrony:x:997:995::/var/lib/chrony:/sbin/nologinaming:x:1000:1000::/home/aming:/bin/bashuser1:x:1001:1001::/home/user1:/bin/bashtcpdump:x:72:72::/:/sbin/nologinnginx:x:996:994:Nginx web server:/var/lib/nginx:/sbin/nologin [[email protected] ~]# wc -l <2.txt10[[email protected] ~]#
时间： 2024-10-03 13:38:48