Shell script (i)

Shell script (i)

1. Common Commands

(1) System Management

#useradd, a user group with the same user name is created by default when a new user is added

#创建用户user1 and specify a UID of 1111, the owning group is 2222 (test), and the home directory is not established

Groupadd test-g 2222

grep test/etc/group

Useradd user1-g 2222-u 1111-m

ID User1

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#创建用户user2 and specify a UID of 1112, the owning group is 2222 (test), and the home directory is established

Useradd user2-g 2222-u 1112

Ls/home

ID User2

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#userdel, home directories are not deleted by default

#删除用户user1和user3 (but does not delete home directories), delete user2 and delete home directories

Userdel user1

Userdel User3

Userdel User2-r

Ls/home

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#usermod, change user4 (1114) ID to 2224, group test to root, home directory to/home/test

Useradd user4-u 1114-g Test

Usermod-g root-u 2224-d/home/test user4

ID user4

grep user4/etc/passwd

Ll/home

Chown-r User4:root/home/test

Ll/home

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#groupadd, add group test1, specify id=2223

Groupadd test1-g 2223

grep test1/etc/group

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#groupmod, rename the group Test1 to test2,id=3333

Groupmod test1-n test2-g 3333

grep test/etc/group

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#groupdel, deleting a group requires confirming that the group has no other members

#删除包含成员的群组将会出错

#删除群组test和test2, the test group has a member delete error

Groupdel test2

Groupdel Test

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#passwd, change password, lock/unlock user, specify minimum/maximum password/warning change time

#更改user4密码为love, only the root user can passwd the user name

passwd User4

Enter Password two times

#锁定用户user4和user5

Passwd-l User4

#在/etc/shadow the 2nd column before adding "! "Indicates that the user is locked

grep User4/etc/shadow

#解锁用户user4

Passwd-u User4

grep User4/etc/shadow

#指定user4密码最短更改时间2天, up to 7 days, 3 days before expiry warning

passwd user4-n 2-x 7-w 3

grep User4/etc/shadow

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#chgrp, change the file or directory group, changing the mount.sh group from root to test

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(2) file directory management

#ls,-L is displayed in long format and 1-7 columns are:

#文件类型和权限, number of links, file owner, file group, file size, last modified time, file name

#ls, displays all files in the specified directory, contains hidden files, size in M, and sorted by modified time

LS ALC block-size=m/home

#不足1M以1M算, less than 1G is calculated in 1G

The difference between #与-A and-A is that the former does not show "." (current directory) and ".." (Top level directory)

LS ALC block-size=g/home

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#ls默认以1行显示所有文件和目录, but does not contain subdirectories

Ls/home

#前者1行显示完, which takes 1 lines per file or directory

Ls-1/Home

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#在目录后加反斜杠

Ls-p/Home

Ls-lp/home

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#递归式显示, the UID and GID are replaced by numeric values and sorted alphabetically

#-r: Recursive display,-n:uid,gid value display,-R: Alphabetical order

Ls-r-n-r-al/home

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#cp, the directory cannot be copied by default without parameters

#-a: Preserve links, file attributes, and recursively replicate directories

#-d: Reserved link,-f: Overwrite destination file and do not prompt,-P: With copy modification time and access time

#-r: Recursive copy directory, target must be directory,-L: Do not copy file, just link file

#将/Home Copy to/tmp with all attributes, and force overwrite of destination file

Cp-apf/home/tmp

Ls/tmp

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#mv,-F: Force overwrite of target file and do not prompt, new version has default reserved permission

#将/home/aaa file is moved to/TMP and retains permissions, such as the destination file exists with the same overwrite

Ls-kl/home/aaa

Mv-f/home/aaa/tmp

Ll/tmp/aaa

#两者比较, the target file is overwritten and permissions are reserved

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#rm, delete files or directories

#强制删除文件或者目录, if the directory has subdirectories deleted

Rm-rf/tmp/home

Ll/tmp

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#mkdir, set up directory,-P: If the path does not exist for some directories,-m: Set permissions

#建立目录/HOME/BBB/CCC, and specify a permission of 777

Mkdir-p-M 777/HOME/BBB/CCC

#-m Specifies the deepest directory permission, and the missing directory permission is the current user's default permission

#此处需要注意的是root的umask为0022, so the BBB permission is 755 instead of 777

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#rmdir, you can only delete empty directories,-p: Recursively delete empty directories if the parent directory is empty and delete

#加上-P, if the parent directory is not empty, prompt for errors, note the difference

Mkdir-p BBB/CCC

Mkdir-p bbb/ddd

Rmdir-p BBB/CCC

LS BBB

Rmdir-p bbb/ddd

Ls

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#stat, view file directories access, modify, and change time

#access为访问时

#modify为修改过内容时间,

#change为修改过状态时间, such as chmod, chown command changed permissions, etc.

Stat mount.sh

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#touch, create an empty file,-A: Modify access time only,-M: modify only the modified time

#-t: Using the specified date,-r: modifies the specified file date to the reference file date

#将访问时间改为20140102030405, modify the time to 20150102030405

Touch-a-T 201401020304.05 BBB

Touch-m-T 201501020304.05 BBB

Stat BBB

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#再将bbb改为参考文件ccc时间

Stat CCC

Touch-r CCC BBB

Stat BBB

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#file, test file type,-B: Do not display file or directory names

File mount.sh

File-b mount.sh

File test

File-b Test

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#ln,-B: Back up before overwriting the target file, append string to backup file,-S: Specify backup string

#-s: Creating a soft link,-D: Creating a hard link

#软链接: Equivalent to shortcut, delete does not affect the original file

#硬链接: Equivalent to the original file of a "special" copy, delete the original file does not affect

#但修改内容同样指向原文件

#为bbb建立软链接, and overwrite the destination file, specify the backup string as ". BK"

Ln-s-b-s BK BBB LNB

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#删除软链接: The original file is not affected, but writes to the original file if the content is written

Cat BBB

echo "Test" >LNB

Cat BBB

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#为bbb建立硬链接, you can see the CCC link value changed from 1 to 2

ln-d CCC Ccchard

LL CCC

#删除硬链接: After the deletion of the original file does not affect, but the original file link value minus 1

LL CCC

echo "Ccchard" >ccchard

Rm-f Ccchard

ll ccc*

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#删除原文件, hard links can also be used, HARDCCC link value changed from 2 to 1

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This article is from the "Love On Action" blog, please be sure to keep this source http://1055745601.blog.51cto.com/5003160/1659230

Shell script (i)