linux学习命令总结③

q789321

　　#cd ~ 回到当前用户的家目录
[root@VM_168_102_centos etc]# pwd
/etc //当前所在目录
[root@VM_168_102_centos etc]# cd ~ //回到当前用户家木里
[root@VM_168_102_centos ~]# pwd
/root //当前用户家目录
[root@VM_168_102_centos ~]# su wanghan
[wanghan@VM_168_102_centos rott]$ cd ~ //回到当前用户家木里
[wanghan@VM_168_102_centos ~]$ pwd
/home/wanghan  //当前用户家目录
[wanghan@VM_168_102_centos ~]$
　　#cd - 回到上一次所在目录

[wanghan@VM_168_102_centos ~]$ cd /etc //切换到/etc目录
[wanghan@VM_168_102_centos etc]$ cd /tmp //从/etc目录切换到/tmp目录
[wanghan@VM_168_102_centos tmp]$ cd -  //从当前/tmp回到上一次所在目录
/etc //回到了/etc
[wanghan@VM_168_102_centos etc]$ cd - //再从/etc回到上一次所在目录
/tmp //回到了/tmp
[wanghan@VM_168_102_centos tmp]$
　　#pwd命令：查看当前工作目录的完整路径

[wanghan@VM_168_102_centos /]$ pwd
/
[wanghan@VM_168_102_centos /]$ cd /etc
[wanghan@VM_168_102_centos etc]$ pwd
/etc
[wanghan@VM_168_102_centos etc]$
　　#mkdir命令：用来创建指定的名称的目录，要求创建目录的用户在当前目录中具有写权限，并且指定的目录名不能是当前目录中已有的目录。
　　mkdir [选项] 目录…

[wanghan@VM_168_102_centos tmp]$ ls
agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid
[wanghan@VM_168_102_centos tmp]$ mkdir /tmp/test
[wanghan@VM_168_102_centos tmp]$ ls
agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  test
　　mkdir –p 目录…

[wanghan@VM_168_102_centos tmp]$ ls
agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  test
[wanghan@VM_168_102_centos tmp]$ mkdir /tmp/wanghan/test
mkdir: cannot create directory `/tmp/wanghan/test': No such file or directory
[wanghan@VM_168_102_centos tmp]$ mkdir -p /tmp/wanghan/test
[wanghan@VM_168_102_centos tmp]$ ls
agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  test  wanghan
[wanghan@VM_168_102_centos tmp]$ ls wanghan
test
[wanghan@VM_168_102_centos tmp]$
　　若创建的路径中有尚不再存的目录即可按照路径全部创建
　　mkdir –v 目录…

[wanghan@VM_168_102_centos tmp]$ mkdir -pv /tmp/a/b/c/d/e/f/abcd
mkdir: created directory `/tmp/a'
mkdir: created directory `/tmp/a/b'
mkdir: created directory `/tmp/a/b/c'
mkdir: created directory `/tmp/a/b/c/d'
mkdir: created directory `/tmp/a/b/c/d/e'
mkdir: created directory `/tmp/a/b/c/d/e/f'
mkdir: created directory `/tmp/a/b/c/d/e/f/abcd'
　　显示创建目录过程的详细信息
　　#rmdir命令：删除已空的目录

[wanghan@VM_168_102_centos tmp]$ ls
a  agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  ceshi  test  wanghan
[wanghan@VM_168_102_centos tmp]$ ls test
test_1
[wanghan@VM_168_102_centos tmp]$ rmdir /tmp/test
rmdir: failed to remove `/tmp/test': Directory not empty  //该目录非空
[wanghan@VM_168_102_centos tmp]$ rmdir /tmp/test/test_1
[wanghan@VM_168_102_centos tmp]$ ls test
[wanghan@VM_168_102_centos tmp]$ rmdir /tmp/test
[wanghan@VM_168_102_centos tmp]$ ls
a  agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  ceshi  wanghan
　　#shell中的引用
　　‘ ’：强引用，变量替换不会进行

[wanghan@VM_168_102_centos tmp]$ num=123
[wanghan@VM_168_102_centos tmp]$ echo $num
123
[wanghan@VM_168_102_centos tmp]$ echo '$num'
$num
　　“ ”：若引用，能够执行变量替换

[wanghan@VM_168_102_centos tmp]$ num=456
[wanghan@VM_168_102_centos tmp]$ echo num
num
[wanghan@VM_168_102_centos tmp]$ echo "num"
num
[wanghan@VM_168_102_centos tmp]$
　　· ·：命令替换，引用命令的执行结果；命令替换的另外一符号：$(命令)；

[wanghan@VM_168_102_centos tmp]$ echo ls /tmp
ls /tmp
[wanghan@VM_168_102_centos tmp]$ echo `ls /tmp`
a agent_cmd.sock ap_1002.pid ap_1004.pid ap_1005.pid ap_1007.pid ap_1008.pid ap_1014.pid ceshi wanghan
　　结合使用：

[wanghan@VM_168_102_centos tmp]$ echo $test
tmp
[wanghan@VM_168_102_centos tmp]$ echo "This is $test"
This is tmp
[wanghan@VM_168_102_centos tmp]$ echo `ls /$test`
a agent_cmd.sock ap_1002.pid ap_1004.pid ap_1005.pid ap_1007.pid ap_1008.pid ap_1014.pid ceshi wanghan
[wanghan@VM_168_102_centos tmp]$ echo "/tmp:`ls /$test`"
/tmp:a
agent_cmd.sock
ap_1002.pid
ap_1004.pid
ap_1005.pid
ap_1007.pid
ap_1008.pid
ap_1014.pid
ceshi
wanghan
　　#创建一个一当前日期时间创建一个目录

[wanghan@VM_168_102_centos tmp]$ date=`date +%Y-%m-%d-%H%M%S`
[wanghan@VM_168_102_centos tmp]$ mkdir -pv /tmp/$date
mkdir: created directory `/tmp/2014-08-04-212053'
[wanghan@VM_168_102_centos tmp]$ ls
2014-08-04-212053  a  agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  ceshi  wanghan
[wanghan@VM_168_102_centos tmp]$
　　#history命令：查看在当前shell进程的保存在缓冲区中的执行过的命令列表，当shell退出时缓冲区的命令会自动化保存至当前用户的家目录中的.bash_history文件中。

[root@VM_168_102_centos ~]# su wanghan
[wanghan@VM_168_102_centos rott]$ history
1  exit
2  history
[wanghan@VM_168_102_centos rott]$ who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$ pwd
/root
[wanghan@VM_168_102_centos rott]$ history
1  exit
2  history
3  who
4  pwd
5  history
[wanghan@VM_168_102_centos rott]$ cat /home/wanghan/.bash_history
exit
[wanghan@VM_168_102_centos rott]$ exit
exit
[root@VM_168_102_centos ~]# su wanghan
[wanghan@VM_168_102_centos rott]$ cat /home/wanghan/.bash_history
exit
history
who
pwd
history
cat /home/wanghan/.bash_history
exit
[wanghan@VM_168_102_centos rott]$
　　！#：通过命令历史列表中的命令编号引用并执行第#条命令

[wanghan@VM_168_102_centos rott]$ history
1  exit
2  history
3  who
4  pwd
5  history
6  cat /home/wanghan/.bash_history
7  exit
8  cat /home/wanghan/.bash_history
9  history
10  history who
11  history pwd
12  history
13  history who
14  exit
15  history
16  who
17  history
[wanghan@VM_168_102_centos rott]$ !3
who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$
！-#：通过命令历史列表中的命令编号引用并执行倒数第#条命令
[wanghan@VM_168_102_centos rott]$ history
1  exit
2  history
3  who
4  pwd
5  history
6  cat /home/wanghan/.bash_history
7  exit
8  cat /home/wanghan/.bash_history
9  history
10  history who
11  history pwd
12  history
13  history who
14  exit
15  history
16  who
17  history
18  who
19*
20  history
[wanghan@VM_168_102_centos rott]$ !-3
who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$
　　！！：执行上一次历史命令

[wanghan@VM_168_102_centos rott]$ pwd
/root
[wanghan@VM_168_102_centos rott]$ !!
pwd
/root
[wanghan@VM_168_102_centos rott]$ !!
pwd
/root
　　! string：执行命令历史列表中最近一次以string开头的命令

[wanghan@VM_168_102_centos rott]$ whatis
usage: whatis keyword ...
[wanghan@VM_168_102_centos rott]$ who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$ !w
who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$
　　！ $：引用上一个命令的最后一个参数，快捷键：Esc .

[wanghan@VM_168_102_centos etc]$ cd /tmp
[wanghan@VM_168_102_centos tmp]$ ls /!$
ls //tmp
2014-08-04-212053  a  agent_cmd.sock  ap_1002.pid  ap_1004.pid  ap_1005.pid  ap_1007.pid  ap_1008.pid  ap_1014.pid  ceshi  wanghan
　　history –c：清空当前缓存中的历史记录

[wanghan@VM_168_102_centos tmp]$ history
1  who
2  pwd
3  history
[wanghan@VM_168_102_centos tmp]$ history -c
[wanghan@VM_168_102_centos tmp]$ history
1  history
　　history –d #：删除与命令历史列表中命令编号相对应的命令记录

[wanghan@VM_168_102_centos tmp]$ history
1  who
2  pwd
3  history
[wanghan@VM_168_102_centos tmp]$ history -d 1
[wanghan@VM_168_102_centos tmp]$ history
1  pwd
2  history
3  history -d 1
4  history
[wanghan@VM_168_102_centos tmp]$
　　history -a：追加当前历史记录保存至命令历史文件中

[wanghan@VM_168_102_centos rott]$ cat /home/wanghan/.bash_history
exit
[wanghan@VM_168_102_centos rott]$ history
1  exit
2  cat /home/wanghan/.bash_history
3  history
[wanghan@VM_168_102_centos rott]$ who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[wanghan@VM_168_102_centos rott]$ pwd
/root
[wanghan@VM_168_102_centos rott]$ histroy -a
bash: histroy: command not found
[wanghan@VM_168_102_centos rott]$ history -a
[wanghan@VM_168_102_centos rott]$ cat /home/wanghan/.bash_history
exit
cat /home/wanghan/.bash_history
history
who
pwd
histroy -a
history -a
[wanghan@VM_168_102_centos rott]$
　　命令历史相关的环境变量：
　　HISTSIZE：命令历史中可以保存的命令个数

[root@VM_168_102_centos ~]# echo $HISTSIZE
1000
　　HISTFILESIZE：命令文件中可以保存的命令个数

[root@VM_168_102_centos ~]# echo $HISTFILESIZE
1000
　　HISTFILE：命令历史文件

[root@VM_168_102_centos ~]# echo $HISTFILE
/root/.bash_history
　　HISTCONTROL：控制命令历史的生成

[root@VM_168_102_centos ~]# echo $HISTCONTROL
ignoredups
　　ignoredups：忽略重复记录的命令，连续相同的命令才算重复

[root@VM_168_102_centos ~]# history
1  history
[root@VM_168_102_centos ~]# who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[root@VM_168_102_centos ~]# who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[root@VM_168_102_centos ~]# history
1  history
2  who
3  history
[root@VM_168_102_centos ~]# who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[root@VM_168_102_centos ~]# history
1  history
2  who
3  history
4  who
5  history
[root@VM_168_102_centos ~]#
　　ignorespace：不记录以空白字符开头的命令

[root@VM_168_102_centos ~]# echo $HISTCONTROL
ignoredups
[root@VM_168_102_centos ~]# HISTCONTROL=ignorespace
[root@VM_168_102_centos ~]# echo $HISTCONTROL
ignorespace
[root@VM_168_102_centos ~]# history
1  history
2  echo $HISTCONTROL
3  HISTCONTROL=ignorespace
4  echo $HISTCONTROL
5  history
[root@VM_168_102_centos ~]#  who
root     pts/0        Aug  4 19:11 (222.36.253.150)
[root@VM_168_102_centos ~]#  pwd
/root
[root@VM_168_102_centos ~]# history
1  history
2  echo $HISTCONTROL
3  HISTCONTROL=ignorespace
4  echo $HISTCONTROL
5  history
6  history
[root@VM_168_102_centos ~]#
　　ignoreboth：同时具有ignoredups和ignorespace的特性
　　shell中的变量赋值：
　　变量名=值

[root@VM_168_102_centos ~]# num=123
[root@VM_168_102_centos ~]# echo $num
123
　　注意：变量在赋值时不能使用$
　　变量名只能包含字母、数字和下划线，而且不能以数字开头
　　变量名区别大小写

[root@VM_168_102_centos ~]# num=123
[root@VM_168_102_centos ~]# echo $NUM
[root@VM_168_102_centos ~]# echo $num
123