Linux Basics Exercises (ls,tr,useradd,usermod)

0729 Exercises

1. Convert the contents of the/etc/issue file to uppercase and save to the/tmp/issue.out file.

[[Email protected] ~]# TR ' A-Z ' A-Z ' </etc/issue >/tmp/issue.out[[email protected] ~]# Cat/tmp/issue.out\skernel \ r on an \m

2, a Linux user to the root email, request the message titled "Help", the message body is as follows:

Hello, I am Username, the system version is here,pleasehelp me to check it, thanks!

Operating system Version Information

[Email protected] ~]# Mail-s "help" root <<eofi am ' id-nu '; ' Cat/etc/centos-release ' EOF [[email protected] ~]# Cat A | Mail-s "HELP5" root [[email protected] ~]# mail-s "HELP6" root < b [[email protected] ~]# cat bi am Second

3, the/root/file list, displayed as a line, and the file name separated by a space.

one [[email protected] ~]# ls/root/| TR "\ n" "" a anaconda-ks.cfg b C d fish-1.23.1-1.el6.rf.x86_64.rpm initial-setup-ks.cfg lntest lovers.txt Mail two [[EM AIL protected] ~]# ls/root/| Xargs

4. Remove the ' ^m ' character from the Windows text file

[[Email protected] ~]# file Ab.txt ab.txt:ASCII text, with CRLF line Terminators[[email protected] ~]# cat-a ab.txt a^m$ B^m$c[[email protected] ~]# cat-a ab.txt | Tr-d ' ^m ' a$b$

5. The contents of the File1 file are: "1 2 3 4 5 6 7 8 9 10" Calculates the sum of all numbers

[email protected] ~]# Cat File1 | Tr ' + ' | Bc55

6, processing string "Xt.,l 1 jr#! $mn 2 c*/fe3 uz4", keep only the numbers and spaces

[Email protected] ~]# echo "Xt.,l 1 jr#file1mn2 c*/fe3 uz4" | TR-DC ' [0-9] ' 1 12 3 4

7. Display the path variable in a separate row for each directory

[Email protected] ~]# echo $PATH | Tr ': ' \ n '/usr/lib64/qt-3.3/bin/usr/local/sbin/usr/local/bin/sbin/bin/usr/sbin/usr/bin/root/bin

8. Delete blank lines of the specified file

[[email protected] ~]# tr-s ' [[: Space:]] ' < A s refers to merging multiple successive merges into one ABCEFG123AAABBBCCC

9. Display each word (letter) in the file in a separate line with no blank lines

[Email protected] ~]# Cat/etc/fstab | Xargs | TR ' "\ n" ##/etc/fstab#createdbyanaconda

....

10, create user Gentoo, additional group is bin and root, the default shell is/BIN/CSH, the annotated message is "Gentoo distribution"

[Email protected] ~]# useradd-g bin,root-s/bin/csh-c "Gentoo good" Gentoo

11. Create the following user, group, and group memberships

Group with the name Admins

User Natasha, using admins as a subordinate group

User Harry, also use admins as a subordinate group

User Sarah, no interactive login system, and not a member of admins, Natasha,harry,sarah password is CentOS

[Email protected] ~]# useradd-g admins natasha && echo "CentOS" | passwd--stdin natashachanging password for user Natasha.passwd:all authentication tokens updated successfully. [Email protected] ~]# useradd-g admins Harry && echo "CentOS" | passwd--stdin harrychanging password for user Natasha.passwd:all authentication tokens updated successfully. [Email protected] ~]# useradd-s/sbin/nologin Sarah [email protected] ~]# echo "CentOS" | passwd--stdin Harry

This article is from the "Mylinux" blog, make sure to keep this source http://luxiangyu.blog.51cto.com/9976123/1833143

Linux Basics Exercises (ls,tr,useradd,usermod)