Data: current date
Red Hat Linux release 9 (Shrike)
Kernel 2.4.20-8 on an i686
login: user1
[user1@linux user1]$ date
Thu Apr 26 11:22:16CST 2018
[user1@linux user1]$
Cal: View April 2018
[user1@linux user1]$ cal 4 2018
April 2018
day one two three four five six
1 2 3 4 5 6 7
8 9 1011 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30
[user1@linux user1]$
Passwd: change password
[user1@linux user1]$ passwd
Changing password for user user1.
New password:
BAD PASSWORD: it is too short
New password:
Retype new password:
passwd: all authentication tokens updatedsuccessfully.
mkdir ls creates a specified directory and sees
[user1@linux user1]$ mkdir -p./home/mengqc/fil3
[user1@linux user1]$ ls
fil1 fil2 fil3 home
cat: create a file and enter
[user1@linux user1]$ cat >fil1
aaaasdasd
sdasdad
aaaaaaa
aaaaaaa
[user1@linux user1]$
more
[user1@linux user1]$ more fil1
aaaasdasd
sdasdad
aaaaaaa
aaaaaaa
[user1@linux user1]$ y
grep: indicates the line where aa is in the output of fil1
[user1@linuxuser1]$ grep aa fil1
aaaaaaaaaaaaaa
aaaaaaaaaaaaaa
[user1 @ linuxuser1] $
Comn: Compare fil fil2
[user1@linux user1]$ comm fil1 fil2
aaaaaaaaaaaaaa
aaaaaaaaaaaaaa
aaaaaaaaaaaaabbbbbbbbbbbbb
bbbbbbbbbbbbb
bbbbbbbbbbbb
bbbbbbbbbb
[user1@linux user1]$
diff: (1): Compare two files and find their differences
[user1@linux user1]$ diff -c fil3 fil4
*** fil3 2018-05-02 10:39:29.000000000 +0800
--- fil4 2018-05-02 10:40:07,000000000 +0800
***************
*** 1,2 ****
aaa
wo shi zhong guo ren !
--- 1,2 ----
aaa
! wo shi mei guo ren!
[user1@linux user1]$
（2）
[user1@linux user1]$ diff -i fil2 fil4
1,2c1,2
< aaaaaaaaaaaaa
< aaaaaaaaaaaaa
\ No newline at end of file
---
> aaa
> wo shi mei guo ren!
[user1@linux user1]$
rm command to delete files and directories
> wo shi mei guo ren!
[user1@linux user1]$ rm -i fil1 fil2
rm: delete general file 'fil1'? y
rm: delete general file 'fil2'? y
[user1@linux user1]$
mv: command to rename a file or directory
[user1@linux user1]$ mv fil3 fil5
[user1@linux user1]$ ls
aa fil4 fil5
wc: command to specify the number of bytes, words, and lines of the file and display the statistical results
[user1@linux user1]$ wc -cw fil4 fil5
6 24 files4
7 27 fil5
13 51 Total usage
[user1@linux user1]$ who|wc -l
1
[user1@linux user1]$ who|wc fil4
2 6 24 files4
cd pwd change the current path
[user1@linux home]$ pwd user1
/home
[user1@linux home]$ cd user1
[user1@linux user1]$
In is used to create links
[user1@linux fil3]$ ln fil4 fil3
[user1@linux fil3]$ ls -all
Total dosage 16
drwxrwxr-x 2 user1 user1 4096 5月 2 17:53 .
drwxrwxr-x 3 user1 user1 4096 5月 2 17:48 ..
-rw-rw-r-- 2 user1 user1 49 5月 2 17:53 fil3
-rw-rw-r-- 2 user1 user1 49 5月 2 17:53 fil4
[user1 @ linux fil3] $ ls -l
Total usage 8
-rw-rw-r-- 2 user1 user1 49 5月 2 17:53 fil3
-rw-rw-r-- 2 user1 user1 49 5月 2 17:53 fil4
Chmod: used to change or set the access permissions of a file or directory
[user1@linux user1]$ chmod o+w aa
[user1@linux user1]$ ls -l aa
-rw-rw-rw- 1 user1 user1 0 5月 2 10:10 aa
Umask: The command is used to set the mask that restricts the permissions of new files
[user1@linux user1]$ umask 0022
[user1@linux user1]$ umask -S
u = rwx, g = rx, o = rx
[user1@linux user1]$ cat > fil6
666666
[user1@linux user1]$ ls -l
Total dosage 20
-rw-rw-r-- 1 user1 user1 16 5月 2 17:42 fil1
-rw-rw-r-- 1 user1 user1 15 5月 2 17:43 fil2
-rw-rw-r-- 1 user1 user1 12 5月 2 17:43 fil3
-rw-r--r-- 1 user1 user1 7 5月 2 18:06 fil6
drwxrwxr-x 3 user1 user1 4096 5月 2 17:48 home
groups: View the group you belong to
[user1@linux user1]$ groups user1
user1 : user1
chgrp chown: command privileges that only superusers can have
[user1@linux user1]$ su – root
[root@linux root]# ls /home/user1
fil1 fil2 fil3 fil6 home
[root@linux root]# chgrp user2/home/user1/fil1
[root@linux root]# chown user2/home/user1/fil1
[root@linux root]# ls -l /home/user1/fil1
-rw-rw-r-- 1 user2 user2 16 5月 2 17:42 /home/user1/fil1
[root@linux root]#
man
[root@linux root]# man -w
/usr/share/man:/usr/local/share/man:/usr/X11R6/man