Linux Basic Knowledge VI

1. Copy the/etc/rc.d/rc.sysinit file to the/tmp directory and add # to the beginning of the line with at least one whitespace character in the/tmp/rc.sysinit file.

# cp/etc/rc.d/rc.sysinit/tmp# Sed-i ' s/\ (^[[:space:]]\) '/#\1/g/tmp/rc.sysinit

2. Copy the/boot/grub/grub.conf to/tmp directory and delete the white space characters from the beginning of the/tmp/grub.conf file.

# cp/boot/grub/grub.conf/tmpsed-i ' s/^[[:space:]]\+//g '/tmp/grub.conf

3. Delete the # and white space characters in the/tmp/rc.sysinit file that begin with # and followed by at least one white-space character in the line.

# sed-i ' s/^#[[:space:]]\+//g '/tmp/rc.sysinit

4. Add # to the beginning of the first three lines in the/tmp/grub.conf file.

# sed-i ' 1,3s/\ (^.\)/#\1/g '/tmp/grub.conf

5. Change the last 0 of all enabled=0 or gpgcheck=0 in the/etc/yum.repos.d/centos-media.repo file to 1.

# sed-i ' s/enabled=0/enabled=1/g;s/gpgcheck=0/gpgcheck=1/g '/etc/yum.repos.d/centos6-01.repo

6, every 4 hours to perform a backup of the/etc directory, back up to the/backup directory, the saved directory name is the shape of etc-201608300202.

writing a script backupetc.sh

tar-czf/backup/etc-$ (date +\%y\%m\%d\%h\%m)/etc >/dev/null 2>&1# crontab-e* */4 * * * SH backupetc.sh

7, weekly 2,4,6 backup/var/log/messages file to/backup/messages_logs/directory, save the file name like messages-20160830.

#crontab-e* * * * 2,4,6/bin/cp/var/log/messages/logs/messages-$ (date +\%y\%m\%d)

8, every two hours every day to take the current system/proc/meminfo file in the beginning of all the information in the S./stats/memory.txt file.

#crontab-E * */2 * * * grep "^s"/proc/meminfo>>/stats/memory.txt

9. During working days, echo "Howdy" is executed every two hours.

* */2 * * 1-5/bin/echo "Howdy"

Script Programming Exercises

10. Create a directory/tmp/testdir-the current date and time.

#!/bin/bashdir_name=testdir-$ (date +%f%t) mkdir/tmp/$dir _name

11. Create 100 empty files in this directory: file1-file100.

#!/bin/bashfor ((i=1;i<101;i++));d otouch/tmp/$dir _name/file$idone

12. Display the user name of the user who is located in the/etc/passwd file in the first even row;

Sed-n ' n;p '/etc/passwd | Cut-d:-f1

13. Create 10 user user10-user19, password and user name;

#!/bin/bashfor i in ' seq ';d ouseradd user$iecho "User$i" | passwd--stdin User$i;done

14, create 10 empty files file10-file19 in/tmp/;

#!/bin/bashfor i in ' seq ';d o touch/tmp/file$idone

15. Change the file10 and the genus to user10, and so on.

#!/bin/bashfor in ' seq ';d ochown user$i:user$i/tmp/file$idone

This article is from "Bo Zi in the Water" blog, declined to reprint!

Linux Basic Knowledge VI