Linux file and user management practice

1. Display the files or directories in the /etc directory that start with a non-letter followed by a letter and any other characters of any length.

[root@centos7 etc]# ls -d /etc/[^[:alpha:]][:alpha:]*

2. Copy all files or directories starting with p and ending with non-digits in the /etc directory to the /tmp/mytest1 directory.

[root@centos7 etc]# mkdir /tmp/mytest1 && cp -a /etc/[p]*[^[:digit:]] /tmp/mytest1/
[root@centos7 etc]# ls /tmp/mytest1/ #View the results
pam.d passwd- pinforc plymouth pnm2ppa.conf postfix prelink.conf.d profile protocols purple
passwd pbm2ppa.conf pki pm popt.d ppp printcap profile.d pulse python

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

[root@centos7 etc]# tr 'az' 'AZ' < /etc/issue >/tmp/issue.out
[root@centos7 etc]# cat /tmp/issue.out View content
\S
KERNEL \R ON AN \M

4. Please summarize and describe the usage of user and group management commands and complete the following exercises:

(1) Create a group named distro with a GID of 2019.

[root@centos7 etc]# groupadd distro -g 2019
[root@centos7 etc]# getent group distro #Verify distro's GID
distro:x:2019:

(2) Create user mandriva, whose ID number is 1005; the basic group is distro;

[root@centos7 etc]# useradd mandriva -u 1005 -g distro
[root@centos7 etc]# id mandriva #Verify the UID number and basic group of mandriva
uid=1005(mandriva) gid=2019(distro) groups=2019(distro)

(3) Create user mageia, whose ID number is 1100 and whose home directory is /home/Linux;

[root@centos7 etc]# useradd mageia -u 1100 -d /home/linux
[root@centos7 etc]# getent passwd mageia #Verification result
mageia:x:1100:1100::/home/linux:/bin/bash

(4) Add a password to the user mageia, the password is mageedu, and set the user password to expire after 7 days

[root@centos7 etc]# echo "mageedu" | passwd mageia --stdin -x 7
[root@centos7 etc]# getent shadow mageia #Verification results
mageia:!!:18308:0:7:7:::

(5) Delete mandriva but keep its home directory;

[root@centos7 etc]# userdel mandriva
[root@centos7 etc]# ls /home/ #Verification result: the mandriva directory still exists
diyoujia linux mandriva slackware test

(6) Create user slackware, whose ID number is 2002, basic group is distro, and additional group is peguin;

[root@centos7 etc]# useradd slackware -u 2002 -g distro -G peguin
[root@centos7 etc]# id slackware #Verification result
uid=2002(slackware) gid=2019(distro) groups=2019(distro),2020(peguin)

(7) Change the default shell of slackware to /bin/tcsh;

[root@centos7 etc]# chsh slackware -s /bin/tcsh
[root@centos7 etc]# getent passwd slackware #Verification result
slackware:x:2002:2019::/home/slackware:/bin/tcsh

(8) Add an additional group admins for user slackware;

[root@centos7 etc]# usermod slackware -aG admins
[root@centos7 etc]# id slackware #Verification result
uid=2002(slackware) gid=2019(distro) groups=2019(distro),2020(peguin),2021(admins)

The above are all the relevant knowledge points introduced this time. Thank you for your learning. I hope that the content compiled by 123WORDPRESS.COM can help everyone.