linux命令的学习

1.创建一个目录

常用命令有150个。
  1. mkdir make directorys创建目录 ---> mkdir /date
  2. ls list(列表) 列表目录文件 ls -ld /date 查看date目录下目录文件，不加目录就是当前目录 -l(long)长格式 -d(directorys)查看目录
  3. cd change directory 改变目录路径 eg: cd /etc
  • 绝对路径
  • windows绝对路径
  • linux绝对路径 ：必须从"/"开始
  • 相对路径
  • bucongtoukaishid
  1. pwd print work directory 打印工作目录(现实当前所在路径)

2.在linux创建一个目录

  1. touch 创建文件或更新时间戳，如果文件存在，我就只更新时间戳。

3.在文件下面增加一段文字

I am studying Linux.
1. 执行 vi oldboy.txt进入文档编辑模式
2. 然后按'i'或"o"或'a'，进入INsert模式
3. 输入完毕后，按"ESC",选择"wq"退出。 wq: write quit	q:退出，不保存

~vim 复杂编辑器(必须学会一个)~

echo 打印输出内容，配合'>','>>'可以为文件覆盖或者追加内容，还有一个较为复杂不常用的类似命令为'printf'

echo '111
222
333' >> oldgirl.txt

特殊符号：

* >或1> 输出重定向：把前面输出的东西覆盖文件，会清楚原文件的内容
* >>或1>> 输出追加重定向：把前面输出的东西追加给文件，不会清楚
* 0<或< 输入重定向：输入重定向用于改变命令的输入，后面指定输入内容，前面跟文件名
[root@linuxhua data]# echo 1 2 3 4 >1.txt 
[root@linuxhua data]# cat 1.txt 
1 2 3 4
[root@linuxhua data]# xargs -n 2 <1.txt 
1 2
3 4
* 0<<或<< 输入追加重定向 ：追加

red是一个pair ，首位标识

[root@linuxhua data]# cat 1.txt 
	[root@linuxhua data]# cat >>1.txt <<red
	> hauhua
	> is broken why?
	> red
	[root@linuxhua data]# cat 1.txt 
	hauhua
	is broken why?
[root@linuxhua data]# echo yesornot 1>1.txt 2>2.txt
[root@linuxhua data]# cat 1.txt 
yesornot
[root@linuxhua data]# cat 2.txt
执行正确、错误信息存放在2个文件中
[root@linuxhua data]# echo yesornot 1>1.txt 2>2.txt
[root@linuxhua data]# cat 1.txt 
yesornot
[root@linuxhua data]# cat 2.txt 
[root@linuxhua data]# cho error >1.txt 2>2.txt 
[root@linuxhua data]# cat 2.txt
执行正确、错误信息都存在一个文件中
[root@linuxhua data]# echo error to one file &>1.txt 
[root@linuxhua data]# cat 1.txt 
error to one file
[root@linuxhua data]# ech add something &>>1.txt 
[root@linuxhua data]# cat 1.txt
error to one file
bash: ech: command not found...
* cat:concatenate files and print on the standard output

4. 把oldboy.txt文件拷贝到/tmp下

* cp	copy 拷贝文件或者目录，不加参数时，只能拷贝文件
		如果想加目录拷贝，必须加 -r

4.把/data 目录移动到/root下

mv /data /root/
[root@linuxhua /]# dir
	bin   data  etc   lib	 media	opt   root  sbin  sys  usr
	boot  dev   home  lib64  mnt	proc  run   srv   tmp  var
	[root@linuxhua /]# dir /root
	anaconda-ks.cfg  initial-setup-ks.cfg
	[root@linuxhua /]# mv /data /root
	[root@linuxhua /]# dir
	bin  boot  dev	etc  home  lib	lib64  media  mnt  opt	proc  root  run  sbin  srv  sys  tmp  usr  var
	[root@linuxhua /]# dir root
	anaconda-ks.cfg  data  initial-setup-ks.cfg
	[root@linuxhua /]#

6. 进入root目录下的data进行删除操作

rm: remove 移动文件或者目录

[root@linuxhua data]# rm /root/data
rm: cannot remove ‘/root/data’: Is a directory
[root@linuxhua data]# rm 1.txt 
rm: remove regular file ‘1.txt’? yes
[root@linuxhua data]# dir
20200210.txt  2.txt  oldgirl.txt  red  的用法
[root@linuxhua data]# rm red
rm: remove regular empty file ‘red’? yes
[root@linuxhua data]# rm 的用法
rm: remove regular file ‘的用法’? yes
[root@linuxhua data]# dir
20200210.txt  2.txt  oldgirl.txt
[root@linuxhua data]#

-f 强制删除
-fr 强制删除，可删除目录

ps -ef |grep mysql ps -ef 查看所有的进程 grep 筛选 process status

另 提示： rm -fr force recursion 强制 、递归 kill 1548
在控制台执行man ps命令可以查看ps命令后面的命令选项的含义如下：

The options are as follows:

 -A      Display information about other users' processes, including those without controlling ter-
         minals.

 -a      Display information about other users' processes as well as your own.  This will skip any
         processes which do not have a controlling terminal, unless the -x option is also specified.

 -C      Change the way the CPU percentage is calculated by using a ``raw'' CPU calculation that
         ignores ``resident'' time (this normally has no effect).

 -c      Change the ``command'' column output to just contain the executable name, rather than the
         full command line.

 -d      Like -A, but excludes session leaders.

 -E      Display the environment as well.  This does not reflect changes in the environment after
         process launch.

 -e      Identical to -A.

 -f      Display the uid, pid, parent pid, recent CPU usage, process start time, controlling tty,
         elapsed CPU usage, and the associated command.  If the -u option is also used, display the
         user name rather then the numeric uid.  When -o or -O is used to add to the display follow-
         ing -f, the command field is not truncated as severely as it is in other formats.
 
 -G      Display information about processes which are running with the specified real group IDs.

 -g      Display information about processes with the specified process group leaders.

 -h      Repeat the information header as often as necessary to guarantee one header per page of
         information.

 -j      Print information associated with the following keywords: user, pid, ppid, pgid, sess,
         jobc, state, tt, time, and command.

 -L      List the set of keywords available for the -O and -o options.

 -l      Display information associated with the following keywords: uid, pid, ppid, flags, cpu,
         pri, nice, vsz=SZ, rss, wchan, state=S, paddr=ADDR, tty, time, and command=CMD.

 -M      Print the threads corresponding to each task.

 -m      Sort by memory usage, instead of the combination of controlling terminal and process ID.

 -O      Add the information associated with the space or comma separated list of keywords speci-
         fied, after the process ID, in the default information display.  Keywords may be appended
         with an equals (`=') sign and a string.  This causes the printed header to use the speci-
         fied string instead of the standard header.
 
 -o      Display information associated with the space or comma separated list of keywords speci-
         fied.  Multiple keywords may also be given in the form of more than one -o option.  Key-
         words may be appended with an equals (`=') sign and a string.  This causes the printed
         header to use the specified string instead of the standard header.  If all keywords have
         empty header texts, no header line is written.

 -p      Display information about processes which match the specified process IDs.

 -r      Sort by current CPU usage, instead of the combination of controlling terminal and process
         ID.

 -S      Change the way the process time is calculated by summing all exited children to their par-
         ent process.

 -T      Display information about processes attached to the device associated with the standard
         input.

 -t      Display information about processes attached to the specified terminal devices.

 -U      Display the processes belonging to the specified real user IDs.

 -u      Display the processes belonging to the specified usernames.

 -v      Display information associated with the following keywords: pid, state, time, sl, re,
         pagein, vsz, rss, lim, tsiz, %cpu, %mem, and command.  The -v option implies the -m option.

 -w      Use 132 columns to display information, instead of the default which is your window size.
         If the -w option is specified more than once, ps will use as many columns as necessary
         without regard for your window size.  When output is not to a terminal, an unlimited number
         of columns are always used.
 
 -X      When displaying processes matched by other options, skip any processes which do not have a
         controlling terminal.

 -x      When displaying processes matched by other options, include processes which do not have a
         controlling terminal.  This is the opposite of the -X option.  If both -X and -x are speci-
         fied in the same command, then ps will use the one which was specified last.

可见
-e和-A的意思是一样的，即显示有关其他用户进程的信息，包括那些没有控制终端的进程。
-f显示用户id，进程id，父进程id，最近CPU使用情况，进程开始时间等等。

find:五星级命令 查找
-type 文件类型

[root@linuxhua /]# find /root/data -type f -exec rm {} \;
[root@linuxhua /]# dir /root/data
[root@linuxhua /]# cd /root/data
[root@linuxhua data]# touch temprmflie.txt
[root@linuxhua data]# find /root/data -type f -name temprmflie.txt -exec rm {} \;
[root@linuxhua data]# touch 1.txt 2.txt 3.txt
[root@linuxhua data]# dir
1.txt  2.txt  3.txt
[root@linuxhua data]# find /root/data -type f -name '*.txt'
/root/data/1.txt
/root/data/2.txt
/root/data/3.txt
[root@linuxhua data]# find /root/data -type f -name '*.txt'|xargs rm
[root@linuxhua data]# dir
  • 管道 ---------> '|'
    删除 data下类型为文件、名字为'*.log'、修改事件为'15天前'的文件
[root@linuxhua data]# find /root/data -type f -name '*.log' -mtime +15 |xargs rm -f

删除目录

[root@linuxhua data]# find /root/data -type d -name '*.log' -mtime +15 |xargs rm -rf