8.1 shell介紹 8.2 命令歷史 8.3 命令補全和別名 8.4 通配符 8.5 輸入輸出重定向
阿新 • • 發佈：2017-08-31
8.1 shell介紹 8.2 命令歷史 8.3 命令補全和別名 8.4 通配符 8.5 輸入輸出重定向
8.1 shell介紹
8.2 命令歷史
8.3 命令補全和別名
8.4 通配符
8.5 輸入輸出重定向
# Linux shell 基礎
# 8.1 shell 介紹
- 什麽是shell
1. shell 是一個命令解釋器，提供用戶和機器之間的交互
2. 支持特定語法，比如邏輯判斷、循環
3. 每個用戶都可以有自己特定的shell
4. CentOS7 默認shell 為bash （Bourne Agin Shell）
5. 還有zsh、ksh等
```
[[email protected] ~]#
[[email protected] ~]# yum list |grep zsh
autojump-zsh.noarch 22.3.0-3.el7 epel
zsh.x86_64 5.0.2-25.el7_3.1 updates
zsh-html.x86_64 5.0.2-25.el7_3.1 updates
zsh-lovers.noarch 0.9.0-1.el7 epel
[[email protected] ~]# yum list |grep ksh
ksh.x86_64 20120801-26.el7 base
mksh.x86_64 46-5.el7 base
python-XStatic-Rickshaw.noarch 1.5.0.0-4.el7 epel
python-moksha-common.noarch 1.2.3-2.el7 epel
python-moksha-hub.noarch 1.4.8-1.el7 epel
python-moksha-wsgi.noarch 1.2.2-2.el7 epel
[[email protected] ~]#
```
# 8.2 命令歷史
- 很多系統裏面的命令都是存在用戶的家目錄下， /root/.bash_history
```
[[email protected] ~]# ls /root/.bash_history
/root/.bash_history
[[email protected] ~]# cat /root/.bash_history
echo $?
yum list |grep -i apr
yum list |grep -i pcre
yum install -y pcre.x86_64
yum install -y pcre-devel.x86_64
./configure --prefix=/usr/local/apache2
echo $?
make
echo $?
make install
echo $?
ls /usr/local/apache2
init 0
[[email protected] ~]#
[[email protected] ~]# echo $HISTSIZE
1000
[[email protected] ~]#
```
- 這是我們之前存的命令，這個文件裏最大可以存1000條
- histroy -c 僅僅是把內存當中的命令給清空了，並不會去刪除配置文件
```
[[email protected] ~]# history -c
[[email protected] ~]# history
8 history
[[email protected] ~]# cat .bash_history
[[email protected] ~]# ls -l .bash_history
-rw-------. 1 root root 15810 8月 12 23:03 .bash_history
[[email protected] ~]#
```
- 變量HISTSIZE 可以定義的，在/etc/profile
```
[[email protected] ~]# vi /etc/profile
HOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=1000
if [ "$HISTCONTROL" = "ignorespace" ] ; then
export HISTCONTROL=ignoreboth
else
export HISTCONTROL=ignoredups
fi
export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL
# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
```
- 可以把HISTSIZE=1000 改為5000 保存
```
HOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=5000
if [ "$HISTCONTROL" = "ignorespace" ] ; then
export HISTCONTROL=ignoreboth
else
export HISTCONTROL=ignoredups
fi
export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL
# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
-- INSERT --
```
- 雖然改了，但是並沒有生效
```
[[email protected] ~]# vi /etc/profile
[[email protected] ~]# echo $HISTSIZE
1000
[[email protected] ~]#
```
- 使用命令source /etc/profile 或者重新進入終端，才會生效
```
[[email protected] ~]# source /etc/profile
[[email protected] ~]# echo $HISTSIZE
5000
[[email protected] ~]#
```
- 會記錄日期時間，這個效果是由環境變量改變的，但是只是在當前終端下生效，
```
[[email protected] ~]# history
8 history
9 cat .bash_history
10 ls -l .bash_history
11 vi /etc/profile
12 echo $HISTSIZE
13 source /etc/profile
14 echo $HISTSIZE
15 history
[[email protected] ~]#
改變命令歷史的格式
[[email protected] ~]# HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S "
[[email protected] ~]# echo $HISTTIMEFORMAT
%Y/%m/%d %H:%M:%S
[[email protected] ~]# history
8 2017/08/14 23:07:03 history
9 2017/08/14 23:09:09 cat .bash_history
10 2017/08/14 23:10:08 ls -l .bash_history
11 2017/08/14 23:28:55 vi /etc/profile
12 2017/08/14 23:33:10 echo $HISTSIZE
13 2017/08/14 23:34:10 source /etc/profile
14 2017/08/14 23:34:13 echo $HISTSIZE
15 2017/08/14 23:35:40 history
16 2017/08/14 23:39:00 HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S "
17 2017/08/14 23:39:15 echo $HISTTIMEFORMAT
18 2017/08/14 23:39:28 history
[[email protected] ~]#
```
- 改變命令歷史的格式，這個只針對當前終端下生效，如果想要所有的都生效，需要編輯vi/etc/profile 文件 把HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " 加入到文件裏面 vi/etc/profile
```
HOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=5000
HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S " 加入這一行
if [ "$HISTCONTROL" = "ignorespace" ] ; then
export HISTCONTROL=ignoreboth
else
export HISTCONTROL=ignoredups
[[email protected] ~]# vi /etc/profile
[[email protected] ~]# source !$
source /etc/profile
[[email protected] ~]#
```
- 這時候再打開另一個終端就可以看到生效了
```
[[email protected] ~]# echo $HISTTIMEFORMAT
%Y/%m/%d %H:%M:%S
[[email protected] ~]#
987 2017/08/14 23:46:55 echo $?
988 2017/08/14 23:46:55 yum list |grep -i apr
989 2017/08/14 23:46:55 yum list |grep -i pcre
990 2017/08/14 23:46:55 yum install -y pcre.x86_64
991 2017/08/14 23:46:55 yum install -y pcre-devel.x86_64
992 2017/08/14 23:46:55 ./configure --prefix=/usr/local/apache2
993 2017/08/14 23:46:55 echo $?
994 2017/08/14 23:46:55 make
995 2017/08/14 23:46:55 echo $?
996 2017/08/14 23:46:55 make install
997 2017/08/14 23:46:55 echo $?
998 2017/08/14 23:46:55 ls /usr/local/apache2
999 2017/08/14 23:46:55 init 0
1000 2017/08/14 23:46:57 clear
1001 2017/08/14 23:47:07 echo $HISTTIMEFORMAT
1002 2017/08/14 23:48:13 history
[[email protected] ~]#
```
- 改變命令歷史的格式就成功了
- 永久保存命令歷史 chattr +a ~/.bash_history
```
[[email protected] ~]# chattr +a ~/.bash_history
```
- 這樣運行過的命令都會記錄下來，
- 但是如果不正常退出，有時候敲了一些命令，但是你沒有logout ，exit 退出，而是直接關閉終端，那樣就會記錄不全，命令就保存的不全。
- 命令 ！！ 2個！其實就是你運行的 上一條命令（最後一條命令）
```
[[email protected] ~]# ls
111 1_heard.txt 1.txt~ 234 3.txt anaconda-ks.cfg.1
123 1_sorft.txt 1.txt.bak 2.txt.bak 4.txt biji.txt
[[email protected] ~]# !!
ls
111 1_heard.txt 1.txt~ 234 3.txt anaconda-ks.cfg.1
123 1_sorft.txt 1.txt.bak 2.txt.bak 4.txt biji.txt
[[email protected] ~]#
```
- !n 表示運行history裏面的第n條命令
```
[[email protected] ~]# history
8 2017/08/14 23:07:03 history
9 2017/08/14 23:09:09 cat .bash_history
10 2017/08/14 23:10:08 ls -l .bash_history
11 2017/08/14 23:28:55 vi /etc/profile
12 2017/08/14 23:33:10 echo $HISTSIZE
13 2017/08/14 23:34:10 source /etc/profile
14 2017/08/14 23:34:13 echo $HISTSIZE
15 2017/08/14 23:35:40 history
16 2017/08/14 23:39:00 HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S "
17 2017/08/14 23:39:15 echo $HISTTIMEFORMAT
18 2017/08/14 23:39:28 history
19 2017/08/14 23:43:15 vi /etc/profile
20 2017/08/14 23:45:50 source /etc/profile
21 2017/08/14 23:51:50 chattr +a ~/.bash_history
22 2017/08/14 23:54:18 history
23 2017/08/14 23:55:50 ls
24 2017/08/14 23:56:13 history
[[email protected] ~]# !10
ls -l .bash_history
-rw-------. 1 root root 15881 8月 14 23:51 .bash_history
[[email protected] ~]#
```
- !word 它會在命令歷史裏面倒著往上找第一個有word的命令
- 比如運行命令!echo 就是運行命令歷史裏 倒著數第一個有ehco 相關的命令
```
[[email protected] ~]# history
8 2017/08/14 23:07:03 history
9 2017/08/14 23:09:09 cat .bash_history
10 2017/08/14 23:10:08 ls -l .bash_history
11 2017/08/14 23:28:55 vi /etc/profile
12 2017/08/14 23:33:10 echo $HISTSIZE
13 2017/08/14 23:34:10 source /etc/profile
14 2017/08/14 23:34:13 echo $HISTSIZE
15 2017/08/14 23:35:40 history
16 2017/08/14 23:39:00 HISTTIMEFORMAT="%Y/%m/%d %H:%M:%S "
17 2017/08/14 23:39:15 echo $HISTTIMEFORMAT
18 2017/08/14 23:39:28 history
19 2017/08/14 23:43:15 vi /etc/profile
20 2017/08/14 23:45:50 source /etc/profile
21 2017/08/14 23:51:50 chattr +a ~/.bash_history
22 2017/08/14 23:54:18 history
23 2017/08/14 23:55:50 ls
24 2017/08/14 23:56:13 history
[[email protected] ~]# !10
ls -l .bash_history
-rw-------. 1 root root 15881 8月 14 23:51 .bash_history
[[email protected] ~]# !echo
echo $HISTTIMEFORMAT
%Y/%m/%d %H:%M:%S
[[email protected] ~]#
```
- 命令歷史裏 關於ehco的命令是 echo $HISTTIMEFORMAT%Y/%m/%d %H:%M:%S，所以 ！echo 就是運行這個命令echo $HISTTIMEFORMAT%Y/%m/%d %H:%M:%S
# 8.3 命令補全和別名
- 按tab一下補全命令，tab按倆下 列出以命令開頭的命令
```
[[email protected] ~]# ls
ls lsblk lsinitrd lslocks lsmod lspci
lsattr lscpu lsipc lslogins lsns lsscsi
[[email protected] ~]# mk
mkdict mkfifo mkfs.ext2 mkfs.xfs mknod
mkdir mkfs mkfs.ext3 mkhomedir_helper mkpasswd
mkdumprd mkfs.btrfs mkfs.ext4 mkinitrd mkswap
mke2fs mkfs.cramfs mkfs.minix mklost+found mktemp
[[email protected] ~]# mktemp
```
- 運行mk tab倆下就會顯示一堆以mk開頭的命令，按mkt tab一下就會自動補全mktemp
- centos7 裏面支持參數補全
1. 需要安裝一個包
```
[[email protected] ~]# systemctl restart network^C
[[email protected] ~]# yum install -y bash-completion
已安裝:
bash-completion.noarch 1:2.1-6.el7
完畢！
[[email protected] ~]#
```
2. 安裝完需要重啟下系統才可以reboot 或者 init 6
3. 重啟系統之後，先看下那個包是否安裝，然後輸入部分命令嘗試按下tab 看看是否會補全
```
[[email protected] ~]# rpm -qa bash-completion
bash-completion-2.1-6.el7.noarch
[[email protected] ~]# systemctl res
rescue reset-failed restart
[[email protected] ~]# systemctl res
rescue reset-failed restart
[[email protected] ~]# systemctl res
rescue reset-failed restart
[[email protected] ~]# systemctl restart network
network-online.target network.service
[[email protected] ~]# systemctl restart network.service
[[email protected] ~]#
```
- alias 別名 給名重新起個名字 用alias 把systemctl restart network.service 改為 restartnet
```
[[email protected] ~]# systemctl restart network.service
[[email protected] ~]# alias restartnet=‘systemctl restart network.service‘
[[email protected] ~]# restartnet
把系統裏所有的alias 都列出來
[[email protected] ~]# alias
alias 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] ~]#
```
- 取消自定義別名
```
[[email protected] profile.d]# unalias restartnet
[[email protected] profile.d]# restartnet
-bash: restartnet: 未找到命令
[[email protected] profile.d]#
```
- 這些alias存在哪裏呢 .bashrc ， /etc/profile.d
```
[[email protected] ~]# vi .bashrc
# .bashrc
# User specific aliases and functions
alias rm=‘rm -i‘
alias cp=‘cp -i‘
alias mv=‘mv -i‘
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
~
~
```
2. 這個/etc/profile.d文件下面的 colorls.sh ，colorgrep.sh 也有
```
[[email protected] ~]# cd /etc/profile.d
[[email protected] profile.d]# ls
256term.csh colorgrep.csh colorls.sh less.csh vim.sh
256term.sh colorgrep.sh lang.csh less.sh which2.csh
bash_completion.sh colorls.csh lang.sh vim.csh which2.sh
[[email protected] profile.d]# vi colorls.sh
~
".bashrc" 12L, 176C
alias ll=‘ls -l‘ 2>/dev/null
alias l.=‘ls -d .*‘ 2>/dev/null
INCLUDE=
COLORS=
for colors in "$HOME/.dir_colors.$TERM" "$HOME/.dircolors.$TERM" "$HOME/.dir_colors" "$HOME/.dircolors"; do
[ -e "$colors" ] && COLORS="$colors" && INCLUDE="`/usr/bin/cat "$COLORS" | /usr/bin/grep ‘^INCLUDE‘ | /usr/bin/cut -d ‘ ‘ -f2-`" && break
done
/alias
```
3. colorgrep.sh 文件也有
```
# color-grep initialization
/usr/libexec/grepconf.sh -c || return
alias grep=‘grep --color=auto‘ 2>/dev/null
alias egrep=‘egrep --color=auto‘ 2>/dev/null
alias fgrep=‘fgrep --color=auto‘ 2>/dev/null
~
"colorgrep.sh" 7L, 201C
```
# 8.4 通配符
- *.txt *表示任何字符
```
[[email protected] ~]# ls
111 1_heard.txt 1.txt~ 234 3.txt anaconda-ks.cfg.1
123 1_sorft.txt 1.txt.bak 2.txt.bak 4.txt biji.txt
[[email protected] ~]# ls *.txt
1_heard.txt 1_sorft.txt 3.txt 4.txt biji.txt
[[email protected] ~]# ls *txt
1_heard.txt 1_sorft.txt 3.txt 4.txt biji.txt
[[email protected] ~]# ls *txt*
1_heard.txt 1_sorft.txt 1.txt~ 1.txt.bak 2.txt.bak 3.txt 4.txt biji.txt
[[email protected] ~]# ls 1*
1_heard.txt 1_sorft.txt 1.txt~ 1.txt.bak
111:
12.tx~ 12.txt 12_txt.swp 222 4913 aming3
123:
aminglinux.log yum.log
[[email protected] ~]#
```
- ls ?.txt ?表示一個字符 任意的字符
```
[[email protected] ~]# touch 2.txt
[[email protected] ~]# touch 1.txt
[[email protected] ~]# ls ?.txt
1.txt 2.txt 3.txt 4.txt
[[email protected] ~]# touch a.txt
[[email protected] ~]# touch bb.txt
[[email protected] ~]# ls ?.txt
1.txt 2.txt 3.txt 4.txt a.txt
[[email protected] ~]#
```
- ls [0-9].txt []13.txt 或者的意思
```
[[email protected] ~]# ls [0-3].txt
1.txt 2.txt 3.txt
[[email protected] ~]# ls [123].txt
1.txt 2.txt 3.txt
[[email protected] ~]# ls [23].txt
2.txt 3.txt
[[email protected] ~]# ls [13].txt
1.txt 3.txt
[[email protected] ~]# ls [0-9].txt
1.txt 2.txt 3.txt 4.txt
[[email protected] ~]# ls [0-9a-zA-Z].txt
1.txt 2.txt 3.txt 4.txt a.txt
[[email protected] ~]#
```
- ls {1,2}.txt
```
[[email protected] ~]# ls {1,2}.txt
1.txt 2.txt
[[email protected] ~]# ls {1,2,3,a}.txt
1.txt 2.txt 3.txt a.txt
[[email protected] ~]#
```
## 8.5 輸入輸出重定向
- [ ] > 正確的輸出重定向 cat 1.txt >2.txt
- [ ] >> 正確的追加 cat 1.txt >>2.txt
- 2> 錯誤的輸出重定向 ls aaa.txt 2>err
- 2>> 錯誤的追加 ls aaa.txt 2>>err
```
[[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] ~]# lsaaa 2>>a.txt
[[email protected] ~]# cat a.txt
-bash: lsaaa: 未找到命令
-bash: lsaaa: 未找到命令
[[email protected] ~]# > >> 2> 2>> >+2> == &>^C
[[email protected] ~]#
```
- &> 可以把正確和錯誤的放一起
```
[[email protected] ~]# ls [12].txt aaa.txt &> a.txt
[[email protected] ~]# cat a.txt
ls: 無法訪問aaa.txt: 沒有那個文件或目錄
1.txt
2.txt
[[email protected] ~]#
```
- &> 同樣也支持追加
```
[[email protected] ~]# ls [12].txt aaa.txt &>> a.txt
[[email protected] ~]# cat a.txt
ls: 無法訪問aaa.txt: 沒有那個文件或目錄
1.txt
2.txt
ls: 無法訪問aaa.txt: 沒有那個文件或目錄
1.txt
2.txt
[[email protected] ~]#
```
- &> 既可以放正確也可以發個錯誤的輸出信息 保存到指定的文件裏
```
[[email protected] ~]# ls [12].txt aaa.txt > 1.txt 2>a.txt
[[email protected] ~]# cat 1.txt
1.txt
2.txt
[[email protected] ~]# cat a.txt
ls: 無法訪問aaa.txt: 沒有那個文件或目錄
[[email protected] ~]#
```
- 輸入重定向 把右邊的一個文件，文件的內容 給它左邊 輸入到一個命令裏面去
```
[[email protected] ~]# wc -l < 1.txt
2
[[email protected] ~]# 2.txt < 1.txt
-bash: 2.txt: 未找到命令
[[email protected] ~]#
```
- [ ] 左邊必須是一個命令，不可以是文件 輸入重定向用的比較少，做一個了解8.1 shell介紹 8.2 命令歷史 8.3 命令補全和別名 8.4 通配符 8.5 輸入輸出重定向