Use of Linux Grep,sed,awk and diff

1:grep// Display Lines

# grep ' main '/home/myhome/a.c//displays the A.C containing the main line

# grep-v ' main '/HOME/MYHOME/A.C//display all rows except main

# grep-n ' The ' a.c//show A.C contains the line

# grep-vn ' The ' a.c//shows no Line

# grep-in ' The ' a.c//does not consider the case

# grep-n T[ae]st a.c//[] Count only one character and search for rows containing test and tast

# grep-n ' [^g]st ' a.c//show St's line but the St is not near the G

# grep-n [^a-g]st a.c//st front cannot have lowercase

# grep-n ' ^the ' A.C//Find only the first character of the line

# grep-n ' ^[a-z] ' a.c//starts with a lowercase letter line

# grep-n ' ^[^a-za-z] ' A.C//is not the beginning of the English alphabet line, ^ in the [] table counter-selected in the outer position at the beginning of the

# grep-n ' \.$ ' A.C//. For the vulgar meaning, use the escape character \ To find the last line that is. No $ will look for a bit of line

# grep-n ' ^$ ' A.C//blank line, only first line and last line

# grep-n ' t. T ' A.C//.. Table any character, such as test,tast, etc.

# grep-n ' 0* ' a.c//0 or spaces, so all the data will be displayed

# grep-n ' 00* ' A.C//so contains 0 lines

# grep-n ' 000* ' a.c mean at least two lines of 0

# grep-n ' t*t ' a.c//so contains t lines, t* denotes spaces

# grep-n ' t.*t ' a.c//must contain two T

# grep-n ' o\{2\} ' a.c//{} range character, special what Suzis asking character with escape character \ Remove particularity, at least two O

# grep-n ' ^# ' A.C//search for lines beginning with #

# grep-n ' d$ ' A.C//tail behavior D

# egrep-n ' go+d ' a.c//extension, more than one O

# egrep-n ' go?d ' a.c//o? Empty or an O

# egrep-n ' Good|goood ' A.C//two or three x O

# NL My_printf.sh | Sed ' 2,5d '//nl print and delete rows 2 to 5

Use of 2:sed

# sed-n ' 3,5 ' p my_printf.sh//print lines

# sed-n ' 1,$ ' P my_printf.sh//Print all Lines

# grep-n '. * ' my_printf.sh | Sed-n ' 3 ' p//prints the third line and displays the line number

# sed-n '/tom/' P my_printf.sh//print a line containing Tom string, using//

# sed-n '/^i/' P my_printf.sh//print I lines beginning with

# sed-n '/!$/' P my_printf.sh//print! End of Line

# sed-e ' 1 ' p-e '/T/' p-n my_printf.sh//e equivalent to the conveyor, first print front and then print back

# sed ' 1 ' d my_printf.sh//delete first line

# sed '/yes/' d my_printf.sh Delete rows containing yes

# sed ' 2s/name/myname/g ' my_printf.sh//replace the second row of Name for Myname,g is global, no only replaces the first

# sed ' s/s/myname/g ' my_printf.sh//No line number default replaces all lines

# sed ' 1,4s/s/myname/g ' my_printf.sh//replace 1~4 line

# sed ' s/[0-9]//g ' my_printf.sh//Delete all the numbers

# sed ' s/[a-z]/\u&/g ' my_printf.sh//lowercase letters all replaced with uppercase letters

# sed ' s/[a-z]/\l&/g ' my_printf.sh//uppercase replaced by lowercase

# sed-n ' 3s/[a-z]/\l&/g ' p my_printf.sh//uppercase replace lowercase and print third line

# sed-r ' s/(AM) (. *) (old)/\3\2\1/' my_printf.sh//Exchange location of AM and old,-r table no justification \, () Table fragment

-N: Only available after SED processing

S: Search or replace

P: Print

-e: SED operation directly on the command line

-R: Extending regular Expressions

A: Increase

C: Replace

D: Delete

Use of 3:awk

$: ~# awk ' {print $} ' demo.txt//Print all

$NF: # awk ' {print $NF} ' demo.txt//print last field per line

$: ~# awk ' {print '} ' demo.txt//Print first field

$: ~# awk ' {print $} ' demo.txt//Print Second field

: ~# awk ' {print $ (NF-1), ' OK '} ' demo.txt//print the penultimate line and output OK

: ~# awk ' {print nr,$0} ' demo.txt//Print line number

ENVIRON: ~# awk ' {print environ[' USER '];} ' demo.txt//print path

BEGIN:: ~# awk ' begin{print environ["PATH"];} '//data to be entered before execution of the line

# last-n 5 | awk ' {print '} '///print the first five user information fields

# CAT/ETC/PASSWD | Awk-f ': ' {print '} '//-f the domain delimiter:

# CAT/ETC/PASSWD | Awk-f ': ' {print $ \ t ' $7} '//\t table interval, the account and shell are separate from tab

# awk-f: '/root/'/etc/passwd//Match Pettem (Root) to execute action (output line content is not specified)

# awk-f: '/root/{print $7} '/etc/passwd//contains the root row and prints the corresponding Shel

# awk-f ': ' {print ' file name: ' filename ', line number: ' NR ', line number: ' NF ', Content: ' $/etc/passwd '

# awk-f ': ' {printf ("File name:%10s, line number:%s, line number:%s, Content:%s\n", filename,nr,nf,$0)} '

/etc/passwd

Comparison of 4:diff differences

The function of the diff command in Linux is to compare two text files on a line-by-row basis, listing their differences. It checks the given file for a system and displays all the different rows in the two files without requiring the file to be sorted beforehand. Compare what makes old and new files do!

# Cat F1.txt

Hello

World

# Cat F2.txt

Hello

World_my

Good

# diff F1.txt F2.txt

2c2,3

< world//old files should be reduced in content

---//delimiter

> world_my//What should be added to old files

> Good

;> to add a row of old files just like new files

F1.txt old file content, f2.txt new file content

, "<" means that the following file is 1 lines less than the previous file, corresponding to the old file
">" means that the following file is 1 lines more than the previous file, corresponding to the new file

# diff-u F1.txt F2.txt//Combined comparison

---f1.txt2015-11-26 22:27:06.589702164 +0800

+ + + f2.txt2015-11-26 22:25:47.356186772 +0800

@@ -1,2 +1,3 @@

Hello

-world

+world_my

+good

Generate Patch file Patches

# diff-u F1.txt f2.txt >f1-f2.patch

# Cat F1-f2.patch

---f1.txt2015-11-26 22:27:06.589702164 +0800

+ + + f2.txt2015-11-26 22:25:47.356186772 +0800

@@ -1,2 +1,3 @@

Hello

-world

+world_my

+good

Catalog comparison

Test1 a.txt More Cc;test1 no f1.txt,f2 have f1.txt

# DIFF-UNR Test1 Test2

Diff-unr Test1/a.txt Test2/a.txt

---test1/a.txt2015-11-26 22:52:47.243168226 +0800

+ + + test2/a.txt2015-11-26 22:48:14.669955070 +0800

@@ -1,3 +1,2 @@

Aa

Bb

-cc

Diff-unr Test1/f1.txt Test2/f1.txt

---test1/f1.txt1970-01-01 08:00:00.000000000 +0800

+ + + test2/f1.txt2015-11-26 22:50:13.508227936 +0800

@@ -0,0 +1,2 @@

+hello

+world

Hit patch

# patch F1.txt <f1-f2.patch//Current directory

Undo Patch: # patch-r F1.txt <f1-f2.patch

Directory patching: Put the generated patch files in the old file directory to be patched,

Then: # PATCH-P1 < Test1-to-test2.patch

;-p1 means to cancel the first level directory

Use of Linux Grep,sed,awk and diff