Find grep sed awk detailed

Find: Finds the file specified in the file system. You can find by file name (-name) permission (-perm) attribution.

Find the path expression to locate the file

* Wildcard characters can be added anywhere in the file name

Common examples (refer to find--help for details):

Find. -name 1.txt Find files in current directory and subdirectories 1.txt

Find/tmp-name 1.txt Find files in/tmp directory and subdirectories 1.txt

find/bin/-perm 4755 | The function of the Xargs ls-al pipe symbol is to use the previous output as the following parameter to perform the subsequent part.

Find/tmp-name "1.txt" | -exec ls-l

Find/tmp-name ' *.txt '-exec ls-l {} \;

grep: A powerful text-search tool that uses regular expressions to search for text and print matching lines.

grep [command options] to find the matching pattern [filename to find]

-C Displays the number of matches per line

-I is case insensitive

-N Displays travel numbers and lines

-V does not match to the line output to

-R Recursive Lookup

-a displays matching lines and lines below 3 lines grep-a 3 root/etc/passwd

-B displays matching rows and rows above 3 lines Grep-b 3 root/etc/passwd

-C Displays the matching line and the following and above 3 lines grep-c 3 root/etc/passwd

grep cams/root/1.txt Find Cams string in 1.txt file

Grep-r Cams/root/cams finds the Cams string in all files under the/root/cams directory and its subdirectories, and prints the matching lines.

Grep-a 1 ' root '/etc/passwd
In addition to being able to find files, grep is able to redirect any output stream to grep for lookups:

PS aux | grep Ora finds all process information in the process name that contains Ora

sed : is a good file processing tool, itself is a pipeline command , mainly in line for processing, you can replace the data, delete, add, select and other specific work.

sed parameters [-nefr] Action file

Parameters:

-N: Quiet mode. Only the line (or action) that has been specially processed by SED will be listed.

-F: Write the SED action directly in a file,-f filename, you can run the SED action within filename.

-R: The default is the basic formal French notation

-I: Directly modifies the contents of the read file, not the output to the terminal.

Action:

A: New, a can be followed by a string, and these strings will appear on the next line.

C: Replace, C can be followed by a string.

D: Delete, the back of D does not pick up anything.

I: Insert, I can be followed by strings, these strings will appear on a new line (the current line).

P: printing, print a selected data, general and sed-n combination

S: Replace, can be replaced directly, usually with formal notation. Example: 1,20s/old/new/g replace the first line to the 20th line with new, and g replace all

Common example, you can try the following statement specifically what it means:

The action behind the SED, only with single quotes

nl/etc/passwd | Sed ' 2,5d '
nl/etc/passwd | Sed ' 2d '

nl/etc/passwd | Sed ' 2, $d '
nl/etc/passwd | Sed ' 2a drink tea '

nl/etc/passwd | Sed ' 2i drink tea '

nl/etc/passwd | Sed ' 2a Drink tea or \
Drink beer? '

nl/etc/passwd | Sed ' 2,5c NO 2-5 number '
nl/etc/passwd | Sed-n ' 5,7p '
nl/etc/passwd | Sed-n '/root/p '

nl/etc/passwd | Sed '/root/d '
nl/etc/passwd | Sed-n '/root/{s/bash/blueshell/;p} '

nl/etc/passwd | Sed-n '/bash/{s/bash/bashshell/;p; q} '
Sed ' s/to be replaced by string/new strings/g '

/sbin/ifconfig eth0 | grep ' inet addr ' |sed ' s/^.*addr://g ' | Sed ' s/bcast.*$//g '
/sbin/ifconfig eth0 | grep ' inet addr ' |sed ' s/^.*addr://g '

nl/etc/passwd | Sed-e ' 3, $d '-e ' s/bash/blueshell/'

awk: is a powerful text analysis tool. Typically awk is handled as a unit of the file's behavior, and awk handles the text by executing the corresponding command for each line of the file it receives.

There are three ways to invoke awk:

1. Command line mode (highlights)

2.shell Script Mode

3. Insert all the awk commands into a separate file and then call

Specific examples:

1, last-n 5 | awk ' {print '} ' prints the first column of the preceding five rows (all columns, $ = nth column)

2, CAT/ETC/PASSWD | Awk-f ': ' {print ' \ t ' $7} '

Displays only the first and seventh columns of the/etc/passwd, separated by the TAB key. -f Specifies the domain delimiter as ":".

3, CAT/ETC/PASSWD | Awk-f ': ' BEGIN {print ' Name,shell '} {print $ ', ' $7} END {print ' Blue,/bin/nosh '} '

Only the/etc/passwd account and the shell of the account are displayed, and the account is separated from the shell with a comma, and all rows add the column name Name,shell, adding "Blue,/bin/nosh" to the last line.

4, Awk-f: '/root/{print $7} '/etc/passwd

Search all lines that have the root keyword/etc/passwd and display the corresponding shell.

The following are AWK programming, which can be custom variables, conditional statements (from the C language), loop statements, arrays.

5, awk ' {count++;p rint;} End{print "User Count is", count} '/etc/passwd

Statistics on the number of/ETC/PASSWD accounts
6. awk ' BEGIN {count=0;print ' [Start]user count is ', count} {Count=count+1;print $;} End {print "[end] User Count is", count} '/etc/passwd

This is also the count of/etc/passwd accounts.

It's so much the usual! Write a summary to this, later discovered the new world, come again to add.

Here's the difference between SED and awk:

Awk is a programming language that has a strong ability to handle document data, and awk is adept at extracting data from formatted messages or a large text.

Sed is a streamlined, non-interactive editor that performs the same editing tasks as compiling VI.

Summarize:

1, if the file is formatted, that is, the delimiter is divided into multiple domains, using awk preferentially;

2. awk is suitable for column (domain) operations, and SED is suitable for line-by-row operation.

3. Awk is suitable for extracting files, and sed is suitable for editing files.

Note: the sed and awk edits to the file do not change the file itself, only the output is changed.

Find grep sed awk detailed