shell special symbol cut command
- cut partition, - d separator - f specifies segment number - c specifies the number of characters
- Sort sort, - n in numeric order - r reverse order - t separator - kn1/-kn1,n2
- Wc-l Statistical Lines-m Statistical Characters-w Statistical Words
- uniq de-weighting, - c statistical rows
- tee is similar to > and redirects are displayed on the screen at the same time
- TR replaces characters, tr'a''b', case replaces tr' [a-z]''[A-Z]'
- split cut, - b size (default unit byte), - l line number
cut command
- The cut command is used to intercept a string
- Format: cut - d "splitter" file name
- - d: Following the split character, the split character is enclosed in double quotation marks.
- - f: Following the string
- -c: followed by a few characters
- Interception of paragraphs 1 to 3
[root@linux-128 ~]# head -5 1.txt |cut -d ":" -f 1-3 root:x:0 bin:x:1 daemon:x:2 adm:x:3 lp:x:4
- Interception of paragraphs 1 and 3
[root@linux-128 ~]# head -5 1.txt |cut -d ":" -f 1,3 root:0 bin:1 daemon:2 adm:3 lp:4
- Intercept the second character
[root@linux-128 ~]# head -5 1.txt |cut -c 2 o i a d p
- Intercept the second character to the fifth character
[root@linux-128 ~]# head -5 1.txt |cut -c 2-5 oot: in:x aemo dm:x p:x:
sort command
- The sort command is used for sorting. The format sort [-t splitter] [-kn1, n2] [-nur], n1,n2 refers to numbers.
- -t separator
- -k is sorted by columns; interval ranges are comma-k3,5
- -n sorted by number
- - r in reverse order, sorted from typing to minor
- -u to repeat
- The beginning of the - un letter will be recognized as duplicate content, such as skj1 a weotj will be considered duplicate content, only display digital content.
- sort does not add any options, from the first line character backward, in turn by ASCII code value comparison, sorted by ascending order
[root@linux-128 ~]# vim 2.txt 111 111 111 111aaa 121 !@#$@123 1asd abab abab adm:x:3:4:adm:/var/adm:/sbin/nologin bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin root:x:0:0:root:/root:/bin/bash
- Sort by number
[root@linux-128 ~]# sort -n 2.txt !@#$@123 abab abab adm:x:3:4:adm:/var/adm:/sbin/nologin bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin root:x:0:0:root:/root:/bin/bash 1asd 111 111 111 111aaa 121
- Note: If there are letters or special symbols, they are treated as 0 by default in numeric sorting.
- Reverse sorting
[root@linux-128 ~]# sort -nr 2.txt 121 111aaa 111 111 111 1asd root:x:0:0:root:/root:/bin/bash lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin bin:x:1:1:bin:/bin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin abab abab !@#$@123
- To repeat, look at the letters here as zero, and then repeat.
[root@linux-128 ~]# sort -nu 2.txt abab 1asd 111 121
wc command
- The wc command is used to count the number of lines, characters and words in a document.
- - l Statistical Row Number
- - m Statistical Character Number
- - w Statistics Word Number
- View file 3.txt rows
[root@linux-128 ~]# cat 3.txt abab 1asd 111 121 [root@linux-128 ~]# wc -l 3.txt 4 3.txt
- See how many characters there are in the file 3.txt, $is the end-of-line character
[root@linux-128 ~]# cat -A 3.txt abab$ 1asd$ 111$ 121$ [root@linux-128 ~]# wc -m 3.txt 18 3.txt
- - w statistical word, which is divided by spaces or blank characters.
[root@linux-128 ~]# cat 3.txt abab 1asd 111 121 [root@linux-128 ~]# wc -w 3.txt 4 3.txt
- If wc is followed by no options and directly followed by the document, the number of lines, words and characters will be output in turn.
[root@linux-128 ~]# wc 3.txt 4 4 18 3.txt
uniq command
- The uniq command is used to delete duplicate rows, usually in conjunction with sort.
- The - c option is commonly used to count the number of duplicated rows and to write the number of rows in front
[root@linux-128 ~]# sort 2.txt 111 111 111 111aaa 121 !@#$@123 1asd abab abab adm:x:3:4:adm:/var/adm:/sbin/nologin bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin root:x:0:0:root:/root:/bin/bash
- Sort first and then delete duplicate rows
[root@linux-128 ~]# sort 2.txt |uniq -c 3 111 1 111aaa 1 121 1 !@#$@123 1 1asd 2 abab 1 adm:x:3:4:adm:/var/adm:/sbin/nologin 1 bin:x:1:1:bin:/bin:/sbin/nologin 1 daemon:x:2:2:daemon:/sbin:/sbin/nologin 1 lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin 1 root:x:0:0:root:/root:/bin/bash [root@linux-128 ~]# sort 2.txt |uniq 111 111aaa 121 !@#$@123 1asd abab adm:x:3:4:adm:/var/adm:/sbin/nologin bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin root:x:0:0:root:/root:/bin/bash
tee command
- The file name after the tee command acts like redirection >, but it has one more function on the screen than redirection.
[root@linux-128 ~]# cat 3.txt >4.txt [root@linux-128 ~]# cat 3.txt |tee 4.txt abab 1asd 111 121
- tee-a is equivalent to chase-and-add orientation; it has an additional function to display on the screen.
[root@linux-128 ~]# cat 3.txt |tee -a 4.txt abab 1asd 111 121 [root@linux-128 ~]# cat 3.txt |tee -a 4.txt abab 1asd 111 121 [root@linux-128 ~]# cat 4.txt abab 1asd 111 121 abab 1asd 111 121 abab 1asd 111 121
Command tr
- The tr command is used to replace characters
[root@linux-128 ~]# cat 3.txt |tr 'a' 'A' AbAb 1Asd 111 121 [root@linux-128 ~]# cat 3.txt |tr '[a-z]' '[A-Z]' ABAB 1ASD 111 121
split command
- Split is used to split documents
- Split-l is divided by rows
- Split-b is divided by size
- split -b
[root@linux-128 ~]# mkdir test [root@linux-128 ~]# cd test [root@linux-128 test]# find /etc/ -type f -name "*.conf" -exec cat {} >1.txt \; [root@linux-128 test]# du -sh 1.txt 252K 1.txt [root@linux-128 test]# split -b 50k 1.txt [root@linux-128 test]# ls 1.txt xaa xab xac xad xae xaf
- split –l
[root@linux-128 test]# wc -l 1.txt 6479 1.txt [root@linux-128 test]# split -l 1000 1.txt [root@linux-128 test]# ls 1.txt xaa xab xac xad xae xaf xag
- If the file name is not specified after split, it will be xaa, xab.... Such a file name to access the cut file
- Specify the target partition file name abc.
[root@linux-128 test]# split -l 1000 1.txt abc. [root@linux-128 test]# ls 1.txt abc.aa abc.ab abc.ac abc.ad abc.ae abc.af abc.ag
Special symbols
- Variable prefix,!$combination, which means end of line
- Multiple commands are written on one line, separated by semicolons
- 6550
- Place the command behind it and leave it behind the scenes.
- Redirection > pursuit aggravation orientation > error redirection 2 > error pursuit aggravation orientation 2 > correct and error redirection & >
- [] One of the specified characters, [0-9],[a-zA-Z],[abc]
- | | and &&, between commands
- $: Can be used as an indicator in front of a variable, and! Used in combination, the end of the line is represented in the regular
[root@linux-128 test]# ls /root 11.txt 123 1.txt 2.txt 3.txt anaconda-ks.cfg d6z 11.txt.bak 1a.txt +2 321.txt 4.txt a.txt test 12 1.log 23.txt 321.txt.bak ab.txt b.txt Job number.txt [root@linux-128 test]# ls !$ ls /root 11.txt 123 1.txt 2.txt 3.txt anaconda-ks.cfg d6z 11.txt.bak 1a.txt +2 321.txt 4.txt a.txt test 12 1.log 23.txt 321.txt.bak ab.txt b.txt Job number.txt
- Multiple commands are written on one line and used; partitioned.
[root@linux-128 ~]# cat 2.txt;cat 3.txt 111 111aaa 121 111 abab 1asd abab !@#$@123 111 root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin abab 1asd 111 121
-
~ Home directory, followed by regular matchers
-
Redirection (correct)> overrides previous content
[root@linux-128 ~]# echo "121212">3.txt [root@linux-128 ~]# cat 3.txt 121212
- Pursuit and Acceleration Orientation (Correct)>
[root@linux-128 ~]# echo "ababab">>3.txt [root@linux-128 ~]# cat 3.txt 121212 Ababab
- Error redirection 2 >
[root@linux-128 ~]# cat 5.txt 2>6.txt [root@linux-128 ~]# cat 6.txt cat: 5.txt: No file or directory
- Mistake pursuit aggravation orientation 2 >
[root@linux-128 ~]# cat 6.txt cat: 5.txt: No file or directory cat: 5.txt: No file or directory
- Errors and corrections are redirected to a file.
[root@linux-128 ~]# cat 3.txt 5.txt &> 6.txt [root@linux-128 ~]# cat 6.txt 121212 ababab cat: 5.txt: No file or directory
- Link symbols in shell & & & |;
- & & the following commands will not be executed until the previous commands have been executed successfully; if the previous commands have not been executed successfully, the latter commands will not be executed.
- The previous command is executed unsuccessfully before the latter command is executed; if the former command is executed successfully, the latter command is not executed.
- If the command on the left is successful or not, the command on the back will be executed.