One sentence for common linux O & M commands

Collect Common commands for Linux O & M management and system management. You can only record them for future viewing. You can also share with us. If you have a good command, paste it. This article is being updated.

1. linux Startup Process

Turn on the power --> BIOS boot self-check --> boot program lilo or grub --> kernel boot --> execute init (rc. sysinit, rc) --> mingetty (create a terminal) --> Shell

2. Bind a NIC to multiple IP addresses

# ifconfig eth0:1 192.168.1.99 netmask 255.255.255.0

3. Set DNS and gateway

# echo "nameserver 202.16.53.68" >> /etc/resolv.conf# route add default gw 192.168.1.1

4. pop up and remove the optical drive

# eject# eject -t

5. Use date to query the date of yesterday

# date --date=yesterday

6. query the row number of the empty row in file1.

# grep ^$ file

7. query the rows ending with abc in file1.

# grep abc$ file1

8. Print the file1 file 1st to the third line.

# sed -n '1,3p' file1# head -3 file1

9. Clear files

# true > 1.txt# echo "" > 1.txt# > 1.txt# cat /dev/null > 1.txt

10. Delete all empty directories

# find /data -type d -empty -exec rm -rf {} ;

11. How to batch Delete Empty files (files with size equal to 0) in linux

# find /data -type f -size 0c -exec rm -rf {} ;# find /data -type f -size 0c|xargs rm –f

12. delete files five days ago

# find /data -mtime +5 -type f -exec rm -rf {} ;

13. Delete the duplicate parts of the two files and print other

# cat 1.txt 3.txt |sort |uniq

14. Attackers can exploit the remote server host name.

# echo `ssh $IP cat /etc/sysconfig/network|awk -F = '/HOSTNAME/ {print $2}'`

15. Monitor network card Traffic in real time (install iftop)

# /usr/local/iftop/sbin/iftop -i eth1 -n

16. view the system version

# lsb_release -a

17. Force the user to log out

# pkill -KILL -t pts/1

18. tar backup and Restoration

# tar -g king -zcvf kerry_full.tar.gz kerry# tar -g king -zcvf kerry_diff_1.tar.gz kerry# tar -g king -zcvf kerry_diff_2.tar.gz kerry# tar -zxvf kerry_full.tar.gz# tar -zxvf kerry_diff_1.tar.gz# tar -zxvf kerry_diff_2.tar.gz

19. forward requests from local port 80 to port 8080. The current host's Internet IP address is 202.96.85.46

-A PREROUTING -d 202.96.85.46 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.9.10:8080

20. Execute/usr/bin/httpd. sh once every two hours from to every month.

# crontab -e0 6-12/2 * 11 * /usr/bin/httpd.sh

21. view the processes that occupy port 8080

# netstat -tnlp | grep 8080lsof -i:8080

22. In the Shell environment, how does one view how long the remote Linux system has been running?

# Ssh user @ ip address of the monitored host "uptime"

23. Command for viewing CPU usage

Refresh Every 5 seconds, data with CPU usage on the rightmost side # vmstat 5 top, then sort by Shift + P, by process processor usage # top

24. Command for checking memory usage

Use the free command to view memory usage # free-mtop, Shift + M, and sort by process memory usage # top

25. view disk I/o

Use iostat to view disk I/o of Disk/dev/sdc3, and refresh every two seconds # iostat-d-x/dev/sdc3 2

26. File System Repair

# Fsck-yt ext3/-t specifies the file system-y automatically answers yes to the found question

27. The read command automatically exits after 5 seconds

# read -t 5 

28. What does grep-E-P mean?

-E, -- extended-regexp adopts an extended regular expression. -P, -- perl-regexp adopts regular perl expressions

29. vi Editor (for modification, add, search)

Insert mode

I insert a cursor before the cursor I insert A cursor at the beginning of the cursor line insert a cursor at the end of the line insert o cursor at the bottom of the line insert A row, insert a row at the beginning of the line insert O cursor at the row insert A line, insert G at the beginning of the line to move nG at the beginning of the last line to n + at the beginning of the n line to move n rows, n at the beginning of the line to move n rows up, and the beginning of the line: /str/move from current to right to where str exists :? Str? From the current left to the place where str exists: s/str1/str2/Replace the first str1 with str2: s/str2/str2/g replace all str1 found in the current row with str2: n1, n2s/str1/str2/g replace all str1 found from line n1 to line n2 with str2: 1 ,. s/str1/str2/g replace all str1 from row 1st to the current row with str2 :., $ s/str1/str2/g replace all str1 from the current row to the last row with str2

30. Copy files between linux servers

Copy local file 1. sh to remote 192.168.9.10 server/data/directory # scp/etc/1.sh king@192.168.9.10:/data/copy remote 192.168.9.10 server/data/2. sh file to local/data/directory # scp king@192.168.9.10:/data/2.sh/data/

31 bytes uses the sedcommand to replace the TEST of line 1 of the test.txt file with the TSET.

# sed -i '23s/TEST/TSET/' test.txt# sed -i '23 s/TEST/TSET/' test.txt

32. Enable the history command to display the time

# export HISTTIMEFORMAT="%F %T "

33. How to view the ports opened by the target host 192.168.0.1

# nmap -PS 192.168.0.1

34. How to view Network Connections

# netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'

35. How to view the library files used by the current system

# ldconfig -v

36. How to view the driver version of the NIC

# ethtool -i eth0

37. Use tcpdump to monitor tcp port 80 of host 192.168.0.1

# tcpdump tcp port 80 host 192.168.0.1

38. view other users' email lists

# mial -u king

39. Cutting large files

Split by 1000 lines of each file # split-l 1000 httperr8007.log httperr split by 5 MB per file # split-B 5 m httperr8007.log httperr

40. Merge files

Extract the union of the two files (only one copy of the duplicate rows is retained) # cat file1 file2 | sort | uniq extracts the intersection of the two files (only the files that exist in the two files at the same time are left) # cat file1 file2 | sort | uniq-d Delete the intersection and leave other rows # cat file1 file2 | sort | uniq-u

41. Services Running in print text mode

# chkconfig --list|awk '$5~/on/{print $1,$5}'

42. Delete 0-byte files

# find -type f -size 0 -exec rm -rf {} ;

43. View processes and arrange them by memory size

# ps -e  -o "%C  : %p : %z : %a"|sort -k5 -nr

44. view the number of concurrent http requests and their TCP connection status

# netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'

45. Obtain an IP address

# Ifconfig eth0 | sed-n '2p' | awk '{print $2}' | cut-c 6-30perl to obtain the IP Address: # ifconfig-a | perl-ne 'if (m/^ s * inet (? : Addr :)? ([D.] + ).*? Cast/) {print qq ($ 1n); exit 0 ;}'

46. Obtain the memory size

# free -m |grep "Mem" | awk '{print $2}'

47. view the number of CPU Cores

# cat /proc/cpuinfo |grep -c processor

48. view disk usage

# df -h

49. Check the number of active PHP-cgi Processes

# netstat -anp | grep php-cgi | grep ^tcp | wc -l

50. view the hardware manufacturer

# dmidecode -s system-product-name