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This article mainly explains "what are the commonly used shell commands in Linux system management", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what are the commonly used shell commands in Linux system management"?

1. Displays the top 10 processes consuming memory / CPU

The code is as follows:

Ps aux | sort-nk + 4 | tail

Ps aux | sort-nk + 3 | tail

two。 View the process

Sort by memory from large to small

The code is as follows:

Ps-e-o "% C:% p:% z:% a" | sort-K5-nr

3. Ranked by cpu utilization from large to small

The code is as follows:

Ps-e-o "% C:% p:% z:% a" | sort-nr

3. Check the number of concurrent requests for Apache and their TCP connection status

The code is as follows:

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

4. Find the processes that consume the most disk IO

The code is as follows:

Wget-c http://linux.web.psi.ch/dist/scientific/5/gfa/all/dstat-0.6.7-1.rf.noarch.rpm

Dstat-M topio-d-M topbio

5. Find out the 10 most commonly used commands and the number of times they are used (or the number of ip visited most)

The code is as follows:

Sed-e's / | /\ nnr g'~ / .bash_history | cut-d'- f 1 | sort | uniq-c | sort-nr | head

6. The 10th field in the log indicates the connection time and calculates the average connection time

The code is as follows:

Cat access_log | grep "connect cbp" | awk 'BEGIN {sum=0;count=0;} {sum+=$10;count++;} END {printf ("sum=%d,count=%d,avg=%f\ n", sum,count)

Sum/count)}'

7.lsof command

Lsof abc.txt shows the process of opening the file abc.txt

Lsof-I: 22 know what program port 22 is running now

Lsof-c abc displays the files now opened by the abc process

Lsof-p 12 to see which files are opened by the process with process number 12

8.rsync command (requires only the compressed files for a certain day to be synchronized, and the remote directory remains the same as the local directory)

The code is as follows:

/ usr/bin/rsync-azvR-password-file=/etc/rsync.secrets `find. -name "* $yesterday.gz"-type f `storage@192.168.2.23::logbackup/13.21/

9. Rename the * .sh file in the directory to * .SH

The code is as follows:

Find. -name "* .sh" | sed's /\ (. *\)\ .sh / mv\ 0\ 1.SH'| sh

Find. -name "* .sh" | sed's /\ (. *\)\ .sh / mv &\ 1.SHUnip'| sh (same as the effect above)

10.ssh executes remote programs and displays them locally

The code is as follows:

Ssh-n-l zouyunhao 192.168.2.14 "ls-al / home/zouyunhao"

11.shell segment comments

The code is as follows:

: 8 the partial setting value is a threshold, and this sentence automatically forbids more than a certain number of connections from the same IP found in netstat-an. Change the local ip to the ip address of your server

forty-two。 How do I know which CPU a process is running on?

The code is as follows:

# ps-eo pid,args,psr

forty-three。 Statistics var directory files with M as the size, listed in the form of a list.

The code is as follows:

Find / var-type f | xargs ls-s | sort-rn | awk'{size=$1/1024; printf ("% dMb% s\ n", size,$2);}'| head

Look for files with files larger than 100m in the var directory, and count the number of files

The code is as follows:

Find / var-size + 100m-type f | tee file_list | wc-l

forty-four。 Sed finds and replaces content

The code is as follows:

Sed-I "s/varnish/LTCache/g" `grep "Via"-rl / usr/local/src/varnish- 2.0.4`

Sed-I "s/X-Varnish/X-LTCache/g" `grep "X-Varnish"-rl / usr/local/src/varnish- 2.0.4`

forty-five。 Count the size of the files in the directory (printed by M)

The code is as follows:

Du $1-- max-depth=1 | sort-n | awk'{printf "% 7.2fM->% s\ n", $1DB 1024 7.2fM 2}'| sed's awk /\ ([^ /]\ {1,\}\) $:\ 1g sort'

forty-six。 Several related Statistics about CND implementation

Count the number of directories in a directory

The code is as follows:

Ls-l | awk'/ ^ dplink'| wc-l

Count the number of files in a directory

The code is as follows:

Ls-l | awk'/ ^-/'| wc-l

Count all the files in a directory

The code is as follows:

Find. /-type f-print | wc-l

Count all the subdirectories in a directory

The code is as follows:

Find. /-type d-print | wc-l

Count the size of certain types of files:

The code is as follows:

Find. /-name "* .jpg"-exec wc-c {}\; | awk'{print $1}'| awk'{print a}'

forty-seven。 Remove the first column (e. G. line number code)

The code is as follows:

Awk'{for ($1 Universe 20, "M"): $1 > = 2 cycles 10? ($1 Universe 2 cycles 10, "K"): ($1, "K"): (1, ")} e'

Shaw answer: du-hs $(du-sk. / `ls-F | grep / `| sort-nr | awk'{print $NF}')

It can also be realized, but it is not perfect. But easy to remember.

fifty-two。 Clear linux buffer cache

The code is as follows:

Sync & & echo 3 > / proc/sys/vm/drop_caches

fifty-three。 Converts all current directory file names to lowercase

The code is as follows:

For i in *; do mv "$I"$(echo $I | tr Amurz)"; done

fifty-three。 Several methods of eliminating ^ M in vim

1) dos2uninx filename

2) sed-e's / ^ M / / 'filename

3) in vim: s / ^ M / / gc

4) col-bx

Newfile

5) tr-s "\ r\ n"\ n"

Newfile

fifty-four。 Clear all arp caches

The code is as follows:

Arp-n | awk'/ ^ [1-9] / {print "arp-d" $1}'| sh

fifty-five。 Bind the arp address of a known machine

The code is as follows:

Cat / proc/net/arp | awk'{print $1 "" $4}'| sort-t. -n + 3-4 > / etc/ethers

Perl's

The code is as follows:

Perl-ne m / ^ ([^ #] [^\ s =] +)\ s* (=. * |) / & & printf ("%-35s%s\ n", $1, $2)'/ etc/my.cnf

fifty-five。 Check the ip and number of attacks of ssh brute force attacks

The code is as follows:

Grep-o'[0-9]\ {1 uniq 3\}\. [0-9]\ {1 uniq 3\}\. [0-9]\ {1 recorder 3\}\. [0-9]\ {1 recorder 3\}'/ var/log/secure | sort | uniq-c

At this point, I believe that everyone has a deeper understanding of "what shell commands are commonly used in Linux system management". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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