File contents: cat, more, less
File interception: head, tail
By column extraction: cut
Sort and statistics: sort, wc
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cat [OPTION] ... [FILE] ... // character files for viewing
-E: display linefeed $
-n: to show each line are numbered
-A: show all control characters
-b: non-blank line number
-s: the compressed air line into a continuous row
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Page View
more: Paging File View
more [OPTIONS...] FILE...
-d: display the page and quit tips
less: page after page to view the output file or STDIN
When you view useful commands include:
/ Text search text
n / N skip to the next or previous match
less command is a command to use pager man
less
space to scroll an
Enter key scrolled one
[pagedown]: Scroll down a
[pageup]: a turning direction
may also be entered directly after the colon / highlighted keyword to search for and to be used to the n Find or search backwards before N.
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The first few lines head view files
head failename default display the first ten lines head -n11 passwd file == head -11 passwd // specifies the first few lines of the file view
After a few lines tail view files
tail failename default display after ten lines of a file tail -n11 passwd == tail -11 passwd // file specifies the view after a few lines
tail -f catalina.out trace file new additions, commonly used in the log monitoring
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cut in columns to extract text
cut [OPTION]... [FILE]...
-d DELIMITER: delimiter specified, the default tab
-f FILEDS:
#: # The first field
# # [#]: A plurality of discrete fields, 1,3,6 e.g.
# - #: a plurality of consecutive fields, e.g. 1-6
Mixed use: 1-3, 7
-c cutting by character
Example:
Cut -d: -f1,3 / etc / to the passwd //: as the separator, taking the first and third column
cat / etc / passwd | cut -d : -f1,3 displays a result of this root: 0ens33 the ifconfig | head -2 | tail -1 | TR -s "" | Cut -d "" -f1-3
the ifconfig ens33 | head -2 | tail -1 | TR -s "" | Cut -d "" -f1 , 2,3
Cut -c34-36 // taken of 34-36 characters
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wc Statistics
Total word count of the total number of rows, the total number of bytes, and total number of characters
wc story.txt
39 237 1901 story.txt
The number of bytes the number of rows of words
Common options
-
- -l count only the number of rows
- -w only count the total number of words
- -c only count the total number of bytes
- -m only count the total number of characters
- -L length of the longest line in the display file
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tr
tr '' + // the 'replaced +
tr -s '' // compression space
tr -d '0-9' // delete characters
tr -dc '[0-9 \ n]' in addition to other characters // Delete
tr -s ""% compression and replace
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Sort text sort according to sort column (a character, a character comparison)
Common options
- -r perform the reverse direction (top to bottom) finishing
- -R random ordering
- sort -n perform numerical size
- -f option ignores character case (fold) string
- Repeat line option -u (unique, unique) to delete outputs
- c -t c option is used as the field delimiter
- -k X X column using options as a character-delimited c can be used multiple times to organize
echo {1..10} | tr '' '\ n' | sort -rn // the line to a digital-to-digital, and then sorted according to the number
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the uniq
the uniq commands: delete duplicate lines before and after the input contact from
uniq [OPTION] ... [FILE] ...
-
-
- -c: Displays the number of each row recurring
- -d: show only duplicate rows over
- -u: Display only never duplicate rows
- Note: Continuous repetitive and identical side
-
And the sort often used together with the command:
sort userlist.txt | uniq -c
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grep filter rows
grep [OPTIONS] PATTERN [FILE...]
-
-
- --color = auto: matching the color display of the text
- -m # # second stop after the match
- -v display is not matched to the line pattern
- -i Ignore character case
- -n Display line numbers match
- -C count the number of rows that match
- -o display only the matched character string
- -q silent mode does not output any information
- -A # after, the line #
- -B # before, before the line #
- -C # context, each longitudinal row #
- -e implement the logic or the relationship between the number of options grep -e 'cat' -e 'dog' file
- -w matches whole words
- -E use ERE
- -F equivalent fgrep, does not support regular expressions
- -f file according to the schema file processing
-
nmap -v -sP 172.16.128.0/24 | grep -B1 up // match the previous row containing up line
| grep -e root -e bin or comprises a plurality of condition // comprising or containing root bin
LS | grep -v [ abc] // the file name does not contain three letters abc
cat / etc / centos-release | grep -o "\ <[0-9] \ + \>" | head -1 // match a single number
[root @ centos7 ~] #grep -E "^ ([^:] +):. * \ <\ 1 $" / etc / passwd packet / / extended regular expressions
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Regular Expressions
Character matches :
- . Matches any single character
- [] Matches any single character within a specified range, an example: [wang] [0-9] [az] [a-zA-Z]
- Any single character [^] matches outside the specified range
Match times : after the character to be used in a specified number of times specified for the preceding character to appear
- * Matches any number of times in front of the characters, including zero greedy mode: as long as possible match
- * Any character of any length
- \? Match its preceding character 0 or 1 times
- \ + Matches its preceding character at least once
- \ {N \} matches the preceding character n times
- \ {M, n \} foregoing character matches at least m times, n times at most
- \ {, N \} foregoing character match up n times
- \ {N, \} foregoing character match at least n times
Location anchoring : positioning to appear
- ^ Beginning of a line anchored mode for most of the left
- $ Anchored end of the line, for the rightmost pattern
- ^ $ For pattern matching the PATTERN entire line blank line ^ $ ^ [[: space:]] * $ blank line
- \ <Or \ b word-initial anchor for the left word mode ( word mode : part of a word alphanumeric underscore count, word count other line of demarcation)
- \> Or \ b anchor ending, the right mode for the word
- \ <PATTERN \> matches the entire word
Packet : \ (\) of one or more characters tied together, as a whole process, such as: \ (root \) \ +
Or : \ |
Example: a \ | ba or b C \ | cat C or cat \ (C \ | c \) at Cat or cat
Extended regular expressions
egrep = grep -E
And the difference between the basic regular expression is, there are some places do not slash (\),
Basic regular expressions need to use local slash: \ (\) \ <\> \ {\} \ + \?
Extended regular expressions: \ <\>
ifconfig | grep -oE "(2 [ 0-4] [0-9] | 25 [0-5] | 1 [0-9] [0-9] | [1-9] [0-9]?) (\ (2 [0-4] [ 0-9] |. 25 [0-5] | 1 [0-9] [0-9] |? [1-9] [0-9])) {3 } "// extended regular expression matching ip
ifconfig |grep -Po "((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?)" //perl正则表达式匹配ip
vim %s#^\(/download.*\)/media/\(.*\)\..*$#\1/mp3/\2.mp3 // vim 搜索替代 分组