We collected a bunch of shell scripting skills, I said, \u00a0 I write a blog mainly to make some study notes, to facilitate their access to,<\/p>\n
so I would come up with such an article, there is no incomprehensible. About the origin of these skills, eh,
\nI forgot, it may come from theunixschool, commandlinefu, cool ground network and igigo.net, of course, there are some of my own ideas and experiences,
\nwho cares, into my mind that I of the.
\n0. shell debugging
\nCopy the code code below: sh -x somefile.sh
\nPlus set + x set-x in somefile.sh file
\n1. && || simplified if else
\nCopy the code code below: gzip -t a.tar.gz<\/p>\n
gzip -t a.tar.gz
\nif [[ 0 == $? ]]; then
\necho “good zip”
\nelse
\necho “bad zip”
\nfi<\/p>\n
Can be simplified to: Copy the code code below:<\/p>\n
gzip -t a.tar.gz && echo “good zip” || echo “bad zip”<\/p>\n
2 to determine the file is not empty<\/p>\n
Copy the code following code:<\/p>\n
if [[ -s $file ]]; then
\necho “not empty”
\nfi<\/p>\n
3 Get File Size
\nCopy the code code below:<\/p>\n
stat -c %s $file
\nstat –printf=’%s\\n’ $file
\nwc -c $file<\/p>\n
4 string replacement
\nCopy the code following code:<\/p>\n
${string\/\/pattern\/replacement}
\na=’a,b,c’
\necho ${a\/\/,\/ \/}<\/p>\n
5. Contains substring?
\nstring=”My string”
\nif [[ $string == *My* ]]; then
\necho “It’s there!”
\nfi<\/p>\n
6. rsync backup
\nCopy the code code below:
\nrsync -r -t -v \/source_folder \/destination_folder
\nrsync -r -t -v \/source_folder [user@host:\/destination_folder<\/p>\n
7 batch rename files<\/p>\n
Txt file with all .bak suffix:
\nCopy the code code below:
\nrename ‘.txt’ ‘.txt.bak’ *.txt
\nRemove all bak suffix:
\nrename ‘*.bak’ ” *.bak
\nAll the spaces into underscores:
\nCopy the code code below:
\nfind path -type f -exec rename ‘s\/ \/_\/g’ {} \\;<\/p>\n
The file names are changed to uppercase:
\nCopy the code code below:<\/p>\n
find path -type f -exec rename ‘y\/a-z\/A-Z\/’ {} \\;<\/p>\n
8. for \/ while loop<\/p>\n
for ((i=0; i < 10; i++)); do echo $i; done
\nfor line in $(cat a.txt); do echo $line; done
\nfor f in *.txt; do echo $f; done
\nwhile read line ; do echo $line; done < a.txt
\ncat a.txt | while read line; do echo $line; done
\n9 delete blank lines<\/p>\n
cat a.txt | sed -e ‘\/^$\/d’
\n(echo “abc”; echo “”; echo “ddd”;) | awk ‘{if (0 != NF) print $0;}’<\/p>\n
10. compare file modification time<\/p>\n
[[ file1.txt -nt file2.txt ]] && echo true || echo false
\n[[ file1.txt -ot file2.txt ]] && echo true || echo false<\/p>\n
11. achieve Dictionary structure
\nCopy the code code below: hput () {
\neval “hkey_ $ 1” = “$ 2”
\n}
\nhget () {
\neval echo ‘$ {‘ “hkey_ $ 1” ‘}’
\n}
\n$ Hput k1 aaa
\n$ Hget k1
\naaa<\/p>\n
12 removed from the second row<\/p>\n
Copy the code the code below:
\n$echo ‘a b c d e f’ | cut -d ‘ ‘ -f1,3-
\n$a c d e f
\n13 Save the stderr output to a variable
\nCopy the code the code below:<\/p>\n
$ a=$( (echo ‘out’; echo ‘error’ 1>&2) 2>&1 1>\/dev\/null)
\n$ echo $a
\nerror<\/p>\n
14)
\n3 lines deleted before 14<\/p>\n
$cat a.txt | sed 1,3d<\/p>\n
15. read multiple domains into a variable
\nCopy the code the code below:
\nread a b c <<< “xxx yyy zzz”
\n16. iterate<\/p>\n
Copy the code code below:<\/p>\n
array=( one two three )
\nfor i in ${array[@]}
\ndo
\necho $i
\ndone
\n17 view directory size<\/p>\n
Copy the code following code:<\/p>\n
du \u2013sh ~\/apps<\/p>\n
18 View CPU information
\nCopy the code following code:<\/p>\n
cat \/proc\/cpuinfo
\n19. date<\/p>\n
$ date +%Y-%m-%d
\n2012-12-24
\n$ date +%Y-%m-%d \u2013date \u2018-1 day’
\n2012-12-23
\n$ date +%Y-m-%d \u2013date \u2018Dec 25′
\n2011-12-25
\n$ date +%Y-m-%d \u2013date \u2018Dec 25 \u2013 10 days’
\n2011-12-15
\n20. get the path and file name
\nCopy the code the code below:<\/p>\n
$ dirname \u2018\/home\/lalor\/a.txt’
\n\/home\/lalor
\n$ basename \u2018\/home\/lalor\/a.txt’
\na.txt<\/p>\n
21. union and intersection
\ncomm can be used to seek union, intersection, difference, assuming that there are now two documents a and b,
\nwhich reads as follows:<\/p>\n
Copy the code following code:<\/p>\n
$cat a
\n1
\n3
\n5<\/p>\n
$cat b
\n3
\n4
\n5
\n6
\n7
\n$ cat b
\n3
\n4
\n5
\n6
\n7<\/p>\n
$ comm a b
\n1
\n3
\n4
\n5
\n6
\n7<\/p>\n
$ comm -1 -2 a b # intersection
\n3
\n5<\/p>\n
$ comm a b | sed ‘s\/\\t\/\/g’ # and set
\n1
\n2
\n3
\n4
\n5
\n6
\n7<\/p>\n
$ comm -1 -3 a b | sed ‘s\/\\t\/\/g’ # b-a
\n4
\n6
\n7
\n22. awk complex delimiter<\/p>\n
Multi-character as the delimiter<\/p>\n
Copy the code following code:<\/p>\n
Multiple delimiters 1<\/p>\n
Copy the code the code below:<\/p>\n
$ echo “a||b||c||d” | awk -F ‘[|][|]’ ‘{print $3}’
\nc<\/p>\n
Multiple delimiters 2
\nCopy the code following code:<\/p>\n
$echo “a||b,#c d” | awk -F ‘[| ,#]+’ ‘{print $4}’
\nd<\/p>\n
$echo “a||b##c|#d” | awk -F ‘([|][|])|([#][#])’ ‘{print $NF}’
\nc|#d<\/p>\n
23 generates a random number<\/p>\n
Copy the code the code below:
\necho $ RANDOM<\/p>\n
24. The mode split file<\/p>\n
Copy the code code below:
\ncsplit server.log \/PATTERN\/ -n 2 -s {*} -f server_result -b “%02d.log” -z<\/p>\n
\/ PATTERN \/ used to match a row, the segmentation process starts
\n{*} Based on the matching, segmentation is repeated
\n-s silent mode
\nfilename suffix after -n split, the number of digits
\nfile name prefix -f divided
\nSpecify suffix format -b<\/p>\n
25. get the file name or extension
\nCopy the code following code: var = hack.fun.book.txt
\nvar=hack.fun.book.txt
\necho ${var%.*}
\nhack.fun.book
\necho ${var%%.*}
\nhack
\necho ${var#.*}
\nfun.book.txt
\necho ${var##.*}
\ntxt<\/p>\n
26. to the root account to perform on a command.<\/p>\n
Copy the code the code below:
\n$ sudo !!<\/p>\n
Among them: * !! refers to the previous command * The last parameter $ on a command parameter * on * all * of a command:!!! First three parameters of a command on 3
\nFor example:
\n$ls \/tmp\/somedir
\nls: cannot access \/tmp\/somedir: No such file or directory<\/p>\n
$mkdir !$
\nmkdir \/tmp\/somedir
\n27. use python to build a simple Web server via http:\/\/$HOSTNAME:8000 visit.<\/p>\n
Copy the code the code below:
\npython -m SimpleHTTPServer<\/p>\n
28. in Vim without permission to save the file to edit.<\/p>\n
Copy the code code below :w !sudo tee %
\n29. on a command replaces foo bar, and executed.
\nCopy the code code below: ^foo^bar<\/p>\n
30. quickly backup or copy files.
\nCopy the code code below: cp filename{,.bak}
\n31. ssh keys will be copied to the user @ host to enable SSH login without a password.
\nCopy the code code below: $ssh-copy-id user@host
\n32. the linux desktop recording video.
\nCopy the code code below: ffmpeg -f x11grab -s wxga -r 25 -i :0.0 -sameq \/tmp\/out.mpg
\n33. man Magical
\nCopy the code code below:
\nman ascii
\nman test<\/p>\n
34 on the vim to edit a command<\/p>\n
Copy the code code below: fc
\n35. delete 0 byte files or junk files
\nCopy the code code below:<\/p>\n
find . -type f -size 0 -delete
\nfind . -type f -exec rm -rf {} \\;
\nfind . -type f -name “a.out” -exec rm -rf {} \\;
\nfind . type f -name “a.out” -delete
\nfind . type f -name “*.txt” -print0 | xargs -0 rm -f
\n36 When writing SHELL display multiple lines of information<\/p>\n
Copy the code the code below:<\/p>\n
cat << EOF
\n+————————————————————–+
\n| === Welcome to Tunoff services === |
\n+————————————————————–+
\nEOF<\/p>\n
Note that when you specify the terminator, it must be the only contents of the line, and the line must begin with this character.
\n37 How to build mysql soft link<\/p>\n
Copy the code code below:<\/p>\n
cd \/usr\/local\/mysql\/bin
\nfor i in *
\ndo ln \/usr\/local\/mysql\/bin\/$i \/usr\/bin\/$i
\ndone<\/p>\n
38 to obtain an IP address:
\nifconfig eth0 |grep “inet addr:” |awk ‘{print $2}’|cut -c 6-<\/p>\n
39 the number of open files
\nCopy the code code below: lsof
\n40. Clear zombie process
\nCopy the code code below:<\/p>\n
ps -eal | awk ‘{ if ($2 == “Z”){ print $4}}’ | kill -9
\n41. print only lines<\/p>\n
Copy the code code below:
\nawk ‘!a[$0]++’ file
\n42 print odd line
\nCopy the code code below:
\nawk ‘i=!i’ file
\nawk ‘NR%2’ file<\/p>\n
43. print matching lines after a row
\nCopy the code code below:
\nseq 10 | awk ‘\/4\/{f=4};–f==0{print;exit}’<\/p>\n
44 After printing a line 10 rows behind
\ncat file | grep -A100 string
\ncat file | grep -B100 string # front
\ncat file | grep -C100 string # before and after<\/p>\n
sed -n ‘\/string\/,+100p’<\/p>\n
awk ‘\/string\/{f=100}–f>=0’<\/p>\n
45. get the last argument on the command line
\nCopy the code following code:
\necho ${!#}
\necho ${$#} #wrong attempt
\n46. ??output redirection<\/p>\n
If you would like to you, STDERR and STDOUT output can be redirected to an output file,
\ntherefore, bash provides special redirection symbols &><\/p>\n
ls file nofile &> \/dev\/null<\/p>\n
How do we redirect script inside? Nothing special, and the general redirection same.
\nCopy the code following code:<\/p>\n
#!\/bin\/bash
\n#redirecting output to different locations
\necho “now redirecting all output to another location” &>\/dev\/null
\nThe problem comes if we want to redirect all output to a file it?
\nWe do not want to redirect the output every time about it, as the saying goes, Hermit own good ideas.
\nWe can use exec to permanent redirect, as follows:<\/p>\n
#!\/bin\/bash
\n#redirecting output to different locations
\nexec 2>testerror
\necho “This is the start of the script”
\necho “now redirecting all output to another location”<\/p>\n
exec 1>testout
\necho “This output should go to testout file”
\necho “but this should go the the testerror file” >& 2<\/p>\n
The output is as follows:<\/p>\n
This is the start of the script
\nnow redirecting all output to another location
\nlalor@lalor:~\/temp$ cat testout
\nThis output should go to testout file
\nlalor@lalor:~\/temp$ cat testerror
\nbut this should go the the testerror file
\nlalor@lalor:~\/temp$
\nAdditional ways to redirect:
\nCopy the code following code: exec 3 >> testout
\nCancel redirection:
\nCopy the code following code: exec 3> –<\/p>\n
47. function<\/p>\n
Any variables are global variables defined elsewhere, if you want to define local variables need to add local keywords
\nthe shell function can also be used recursively
\nCopy the code following code:
\n#!\/bin\/bash<\/p>\n
function factorial {
\nif [[ $1 -eq 1 ]]; then
\necho 1
\nelse
\nlocal temp=$[ $1 – 1 ]
\nlocal result=`factorial $temp`
\necho $[ $result * $1 ]
\nfi
\n}<\/p>\n
result=`factorial 5`
\necho $result
\nCreate a library<\/p>\n
The function of a set in another file, and then load the file into the current command by source<\/p>\n
At the command line using the function<\/p>\n
The function is defined in ~ \/ .bashrc in to<\/p>\n
Passing arrays to functions
\nCopy the code the code below:<\/p>\n
#!\/bin\/bash
\n#adding values in an array<\/p>\n
function addarray {
\nlocal sum=0
\nlocal newarray
\nnewarray=(`echo “$@”`)
\nfor value in ${newarray[*]}
\ndo
\nsum=$[ $sum+$value ]
\ndone
\necho $sum
\n}<\/p>\n
myarray=(1 2 3 4 5)
\necho “The original array is: ${myarray[*]}”
\narg1=`echo ${myarray[*]}`
\nresult=`addarray $arg1`
\necho “The result is $result”
\n48. regex
\nMatch ip address: ?d+.d+.d+.d+
\nCommentary: When extracting useful ip address
\nMatch a specific number:
\n^[1-9]d*$ \/\/ match the positive integers
\n^-[1-9]d*$? \/\/ match negative integers
\n^-?[1-9]d*$? \/\/ match integers
\n^[1-9]d*|0$ \/\/ match non-negative integer (positive integer + 0)
\n^-[1-9]d*|0$? \/\/ matching non-positive integers (negative integer + 0)
\n^[1-9]d*.d*|0.d*[1-9]d*$ \/\/ match float
\n^-([1-9]d*.d*|0.d*[1-9]d*)$ \/\/ match negative float
\n^-?([1-9]d*.d*|0.d*[1-9]d*|0?.0+|0)$ \/\/ match float
\n^[1-9]d*.d*|0.d*[1-9]d*|0?.0+|0$ \/\/ match non-negative floating point numbers (positive float + 0)
\n^(-([1-9]d*.d*|0.d*[1-9]d*))|0?.0+|0$? \/\/ matching non-float (negative float + 0 )
\nCommentary: When handling large amounts of data useful to note that amendments to the specific application
\nMatch a specific string:
\n^[A-Za-z]+$ \/\/ match a string of 26 English letters
\n^[A-Z]+$ \/\/ match by 26 uppercase letters of the alphabet composed of a string
\n^[a-z]+$ \/\/ match a string of 26 lowercase letters of the alphabet consisting of
\n^[A-Za-z0-9]+$ \/\/ match the string of numbers and 26 letters of the English
\n^ w + $ \/\/ matching string by numbers, 26 English letters or underscores the<\/p>\n","protected":false},"excerpt":{"rendered":"
We collected a bunch of shell scripting skills, I said, I write a blog mainly to make some study notes, to facilitate their access to,<\/p>\n
so I would come up with such an article, there is no incomprehensible. About the origin of these skills, eh, I forgot, it may come from theunixschool, commandlinefu, cool ground […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3549"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3549"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3549\/revisions"}],"predecessor-version":[{"id":3550,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3549\/revisions\/3550"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3549"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3549"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}