Common basic commands for Linux 02

Cp
Role: Copying files
Common options:
-L Establish a hard link to the source file instead of copying the file
-S creates a symbolic link to the source file instead of copying the file
-P preserves the properties of the source file or directory, including the owner, the owning group, the permissions and the time
-F forcibly copy a file or directory, regardless of whether the destination file or directory already exists
Note: Echo is a echo-,> representative to export the echo to a file,> overwrites the file,>> is to append something to the file
Instance:

[Email protected] ~]# cp/etc/passwd.  [[email protected] ~]# Lspasswd[[email protected] ~]# echo 1 >/A enter 1[[email protected] ~]# cp-l/A a.a establish a hard link [email Protected] ~]# Echo 2 >> a.a input to a.a 2[[email protected] ~]# Cat/a12[[email protected] ~]# cat a.a 12 File/A and home directory AA content Consistent, hard link real-time updates

[[email protected] ~]# touch/tmp/123[[email protected] ~]# chmod 777/tmp/123[[email protected] ~]# ll/tmp/123-rwxrwxrwx . 1 root root 0 Mar 22:59/tmp/123 create file 123 in/tmp and change the permission to 777[[email protected] ~]# cp/tmp/123. [Email protected] ~]# lltotal 0-rwxr-xr-x. 1 root root 0 Mar 18 23:00 123 copy/tmp/123 to current directory, permissions change [[email protected] ~]# cp-p/tmp/123. Cp:overwrite './123 '? Y[[email protected] ~]# lltotal 0-rwxrwxrwx. 1 root root 0 Mar 18 22:59 123 plus-p option, permissions unchanged

Rm
Action: Delete a file or directory
Common options:
-I prompt for deletion before deleting a file
-R Delete Directory
-F Force Delete silent
-V Show Detailed steps
Instance:

[[email protected] ~]# touch 1 2 [[email  protected] ~]# mkdir 3 4[[email protected] ~]# ls1  2   3  4 Create file 1, 2  create directory 3, 4[[email protected] ~]# rm -i 1rm: remove  regular empty file  ' 1 '?  y prompt confirmation before deleting [[EMAIL PROTECTED] ~]# RM 3RM:  cannot remove  ' 3 ':  is a directory cannot delete directory [[email protected] ~]# rm  -r 3rm: remove directory  ' 3 '?  y Plus-r option to delete directory [[email protected]jacken ~]#  ls2  4[[email protected] ~]# rm -rfv *removed  ' 2 ' removed  directory:  ' 4 ' [[email protected] ~]#  force delete silently and display the procedure 

MV
Action: Move or rename a directory or file
Common options:
 -f If the destination file already exists and does not ask for a direct override of
 -i if the destination file (destination) already exists, you will be asked to overwrite
 -u Update
Instance if the destination file already exists and the source file is newer:

[[EMAIL PROTECTED] ~]# TOUCH /TMP/1[[EMAIL PROTECTED] ~]# MV /TMP/1 &NBSP: Move the/TMP/1 to the current directory [[email protected] ~]# ls /tmp/[[email protected] ~]#  ls 1[[email protected] ~]# mv 1 2[[email protected] ~]#  LS2 renaming the file 1 to 2[[EMAIL PROTECTED] ~]# TOUCH /TMP/2[[EMAIL PROTECTED] ~]# MV  -F /TMP/2&NBSP: Current directory with file 2, move/TMP/2 to current directory  -f option to overwrite directly, silently [[email protected] ~]#  Lltotal 0-rw-r--r--.  1 root root 0 mar 18 23:30 2 There is an old file in the current directory 2[[ email protected] ~]# touch  /tmp/2[[email protected] ~]# ll /tmp/ 2-rw-r--r--.  1 ROOT ROOT 0 MAR 18 23:34 /TMP/2 Create a new file in/tmp 2[[email  protected] ~]# mv -u 2 /tmp/2 [[email protected] ~]#  Lltotal 0-rw-r--r--.  1 rOot root 0 mar 18 23:30 2[[email protected] ~]# ll /tmp/2  -rw-r--r--.  1 ROOT ROOT 0 MAR 18 23:34 /TMP/2 Move the current directory from 2 to/TMP in 2, Because the current directory is 2 older, it will not move, tail.

Useradd
Role: Create user
Comment:/etc/default/useradd create user default option,-D Specify home directory, folder should not exist, ID user name, can display user information. The
 ID -G displays the ID of the group to which the user belongs. The
  -G displays the ID of the group to which the user belongs and the additional group.
  -u Display User ID
Common options:
 -d change preset
 -d Specify user home directory
 -r establish system account
 -s Specifies the shell
 -u specified user ID
 -m automatically establishes the user's login directory
 -m do not automatically establish the user's login directory
 -g Specify the group to which the user belongs
 -G the specified user belongs to the attachment group
 -c with the memo text, the memo text is saved in the comment field of the passwd
 -n the group
instance with the name of the user is canceled:

[[Email protected] ~]# useradd user1[[email protected] ~]# tail -1  /etc/passwduser1:x:503:503::/home/user1:/bin/bash Normal User user1[[email protected] ~]#  useradd -s /sbin/nologin -d /123 -u 666 -g 501 -g 503 - c testuser2   user2[[email protected] ~]# id user2uid=666 (user2)   gid=501 (Jacken)  groups=501 (Jacken), 503 (User1) [[Email protected] ~]# tail -1 /etc /passwduser2:x:666:501:testuser2:/123:/sbin/nologin creates a user user2 and cannot log in, the home directory is/123 uid 666, the primary group ID is 501, the additional group ID is 503, Description information for testuser2[[email protected] ~]# useradd -d -s /sbin/nologin  set default logon script Q/ Sbin/nologin[[email protected] ~]# useradd user3[[email protected] ~]# tail  -1 /etc/passwduser3:x:667:667::/home/user3:/sbin/nologin the newly created user default script is/sbin/nologin (depending on/etc/default/ Useradd

Userdel
Role: Delete User
Common options:
-R Even delete user home directory
Instance:

[[email protected]/]# ID user3uid=667 (user3) gid=667 (User3) groups=667 (USER3) [[email protected]/]# Userdel-r User3[[em AIL protected]/]# ID user3id:user3:No Such user delete users User3

This article is from the "Step Into the Linux World" blog, please be sure to keep this source http://linuxnote.blog.51cto.com/9876511/1622062

Common basic commands for Linux 02