grep Common Search

[[email protected] ~]# #grep [-A] [-b] [--color=auto] ' search string ' filename

Option no parameter
-A: The following can be added to the number, for after the meaning, in addition to listing the row, the subsequent n rows are also listed;
-B: The following can be added as a number, for befer meaning, in addition to listing the row, the preceding n rows are also listed
--color=auto can list the correct data color, you can try its magical effect

-C calculates the number of rows that are found to match the      -l query for multiple files only outputs the file name with matching characters in the package. 

-S does not display error messages that do not exist or have no matching text. The grep command plus the-e parameter, which allows extended pattern matching to be used.

Example :

[[email protected] lianxi]# cat sshd_config |egrep-v "^#|^$"     #从sshd_config查找不以 # and $ start line, same [email Protected] lianxi]# cat sshd_config |grep-e-V "^#|^$"

grep regular Expression meta-character set (base set)

The start sign of the line, such as: ' ^grep ' matches all lines that begin with grep. The end flag for the $ line, such as: ' grep$ ' matches all lines ending with grep. Match a non-newline character such as: ' GR.P ' matches gr followed by an arbitrary character followed by P. * Match 0 or more previous characters such as: ' *grep ' matches all of one or more spaces followed by the grep line. * Together with any character represented. [] matches a specified range of characters, such as ' [Gg]rep ' matches grep and grep. [^] matches a character that is not within the specified range, such as: ' [^a-fh-z]rep ' matches a letter that does not contain a-f and h-z, immediately following the line of the Rep. /(.. /) Mark matching characters, such as '/(love/) ' "x\{m\}" repeat characters x,m times, such as: ' O\{5\} ' matches rows containing 5 O. X\{m,\} repeats the character x, at least m times, such as: ' O\{5,\} ' matches at least 5 O of the line "x\{m,n\}" repeats the character X, at least m times, not more than n times, such as: ' O\{5,10\} ' matches the row of 5--10 O. /w matches literal and numeric characters, that is, [a-za-z0-9_], such as: ' G/w*p ' matches with a G followed by 0 or more literal or numeric characters, followed by P. /w/w the inverse of the form, matching one or more non-word characters, such as the dot period and so on. The/b word lock, such as: '/bgrep/b ' only matches grep.

 grep-c "test.txt counts all lines that start with the" 48 "character Grep-i" may "test.txt case-insensitive find" can "  All rows) grep-n "test.txt" displays line numbers; matches the line and line number of the match character "48", same as NL test.txt |grep) grep-v "" "Test.txt show output no characters" 48 "all rows) grep" 471 " Test.txt displays the line where the output character "471" is located) grep "Test.txt" The output begins with the character "48", and after the character "48" is a tab where the line grep "48[34]" test.txt display output begins with the character "48". The third character is "3" or "4" for All rows) grep "[Mm]ay" Test.txt set case lookup: Display output the first character begins with "M" or "M", and the line that ends with the character "Ay" grep "K ... D "test.txt display output the first character is" K ", combined second is any character, the fifth character is" D "in the Row) grep" [a-z][9]d "test.txt display output the first character range is" A-Z ", the second character is" 9 ", the third character is" D "All rows of grep" [35]. 1998 "Test.txt show the first character is 3 or 5, the 23rd character is any, with 1998 end of all rows grep" 4\{2,\} "test.txt pattern appears a chance to find: Display output character" 4 "at least two times repeat all rows grep" 9\{3,\} " Test.txt the chance to find: Display output character "9" at least three times the repetition of all rows grep "9\{2,3\}" test.txt mode chance to find: Display the output character "9" repeated occurrences of the number of times in a certain range, repeating 2 or 3 times all rows Grep-n "^$" test.txt displays the line number of the output blank line ls-l |grep "^d" If you want to query directories in the directory list with: ls-d *ls-l |grep "^d[d]" in a directory to query all files that do not contain directories ls-l |grpe "^d.....x. X "Queries other users and user group members for a catalog collection that has executable permissions  

-----------------------the magic of "grep" requires a lot of discussion, too-----------------------------

[: Alnum:] represents English uppercase and lowercase characters and numbers, also 0-9, A-Z, A-Z

[: Alpha:] represents any English uppercase and lowercase characters, also A-Z, A-Z

[: Blank:] On behalf of the Cheongju grid key not [Tab] button both

[: Cntrl:] represents the keyboard above the control button, also Shaw including CR, LF, Tab, Del. Wait a minute

[:d Igit:] Represents a number, also 0-9

[: Graph:] except for whitespace (Cheongju key not [Tab] button) all other keys

[: Lower:] represents lowercase characters, also a-Z

[:p rint:] represents any word that can be printed out

[:p UNCT:] represents punctuation (punctuation symbol), also: "'?!; : # $...

[: Upper:] On behalf of uppercase characters, also a-Z

[: space:] Any character that generates whitespace, including SPACEBAR, [Tab], CR, etc.

[: Xdigit:] stands for 16 binary numeric type, so includes: 0-9, a-f, a-f digit no character

Note the focus: [: Alnum:], [: Alpha:], [: Upper:], [: Lower:], [:d igit:]

Example: [[email protected] ~]# grep-n ' [^[:lower:]]oo ' test.txt

# that [: Lower:] Represents a A-Z meaning, to [a-z]oo the beginning of the letter to find, parallel travel number

[[email protected] ~]# grep-n ' [[:d igit:]] ' test.txt

#[]:d igit:] stands for the meaning of 0-9.

grep Common Search