ls command

• Function description: Lists a list of files (including subdirectories) in a specified directory, but does not display the contents of the files

• Usage: ls [OPTION]... [FILE]...

  option	Effect
  -a	Show all files, including hidden files
  -A	Show all files except.And..
  -l	Show detailed properties of the file
  -h	Converts the file size in units and displays them in a human-readable manner, resulting in inaccurate values
  -d	View the directory itself instead of its internal file list, which is often used in conjunction with -l and -d.
  -r	Reverse order display
  -R	Recursively shows that if there are files in the directory, it will also print out the files in the directory

Example 1: Display all files in the current directory, including hidden files.

[root@node1 ~]# ls -a
.   anaconda-ks.cfg  .bash_history  .bash_profile  .cache   .cshrc   .viminfo
..  a.sh             .bash_logout   .bashrc        .config  .tcshrc

Example 2: Display all files except.And..In the current directory.

[root@node1 ~]# ls -A
anaconda-ks.cfg  .bash_history  .bash_profile  .cache   .cshrc   .viminfo
a.sh             .bash_logout   .bashrc        .config  .tcshrc

Example 3: ls command displays the contents of the current directory without any parameters.

[root@node1 ~]# ls
anaconda-ks.cfg a.sh 

Example 4:ls command follows a path, displaying the contents under the specified path.

[root@node1 ~]# ls /var/
adm  cache  crash  db  empty  ftp  games  gopher  kerberos  lib  local  lock  log  mail  nis  opt  preserve  run  spool  tmp  yp

Example 5:ls command uses the -l option to display detailed attribute information for a file.

[root@node1 ~]# ls -l
total 68
-rw-------. 1 root root  1652 Jul 25 19:40 anaconda-ks.cfg
-rw-r--r--. 1 root root 48866 Jul 25 19:40 install.log
-rw-r--r--. 1 root root  9451 Jul 25 19:37 install.log.syslog
...

File type:

Example 6:ls command uses the -h option to convert the file size into units and displays them in a human-readable manner, resulting in imprecise values.

[root@node1 ~]# ls -lh
total 68K
-rw-------. 1 root root 1.7K Jul 25 19:40 anaconda-ks.cfg
-rw-r--r--. 1 root root  48K Jul 25 19:40 install.log
-rw-r--r--. 1 root root 9.3K Jul 25 19:37 install.log.syslog
...

Example 7:ls uses the -ld option to view the properties of the directory itself, not the properties of its internal file list.Usually -l and -d are used together.

[root@node1 ~]# ls -ld /var/log/
drwxr-xr-x. 8 root root 4096 May 28 11:21 /var/log/

Example 8:ls command uses the -r option to display the contents of the current directory in reverse order.

[root@www ~]# mkdir /tmp/test
[root@www ~]# cd /tmp/test/
[root@www test]# mkdir {a..f}
[root@www test]# ls -l
total 0
drwxr-xr-x 2 root root 6 Apr  8 03:53 a
drwxr-xr-x 2 root root 6 Apr  8 03:53 b
drwxr-xr-x 2 root root 6 Apr  8 03:53 c
drwxr-xr-x 2 root root 6 Apr  8 03:53 d
drwxr-xr-x 2 root root 6 Apr  8 03:53 e
drwxr-xr-x 2 root root 6 Apr  8 03:53 f
[root@www test]# ls -lr
total 0
drwxr-xr-x 2 root root 6 Apr  8 03:53 f
drwxr-xr-x 2 root root 6 Apr  8 03:53 e
drwxr-xr-x 2 root root 6 Apr  8 03:53 d
drwxr-xr-x 2 root root 6 Apr  8 03:53 c
drwxr-xr-x 2 root root 6 Apr  8 03:53 b
drwxr-xr-x 2 root root 6 Apr  8 03:53 a 

Example 9:ls command uses the -R option to display recursively. If there are files in the directory, it will print the files in the directory as well.

[root@www test]# cd a
[root@www a]# mkdir {a..d} 
[root@www a]# cd ..
[root@www test]# ls -lR
.:
total 0
drwxr-xr-x 6 root root 38 Apr  8 03:56 a
drwxr-xr-x 2 root root  6 Apr  8 03:53 b
drwxr-xr-x 2 root root  6 Apr  8 03:53 c
drwxr-xr-x 2 root root  6 Apr  8 03:53 d
drwxr-xr-x 2 root root  6 Apr  8 03:53 e
drwxr-xr-x 2 root root  6 Apr  8 03:53 f

./a:
total 0
drwxr-xr-x 2 root root 6 Apr  8 03:56 a
drwxr-xr-x 2 root root 6 Apr  8 03:56 b
drwxr-xr-x 2 root root 6 Apr  8 03:56 c
drwxr-xr-x 2 root root 6 Apr  8 03:56 d

./a/a:
total 0