Awk learning practices

1. what kind of shell does instance 1 make the $2 of file1 and file2 different and get the global $0? Note: When comparing the $2 files, make sure that the first column is the same before comparing the 1.1 files and the operation file # catfile000012000002300003040000456000...

1. instance 1
What kind of shell can make the $2 of file1 and file2 different and get the global $0?
Note: When comparing the $2 files, you must compare them only when the first column is the same.
1.1 Operating files
# Cat file1
00001 20
00002 31
00003 04
00004 56
00005 94
00006 73
00007 25
00008 86
19, 00009
00010 52
 
# Cat file2
00001 20
00007 28
00002 32
00004 56
00010 52
 
1.2 Implementation commands
# Paste file1 file2 | awk '{if ($1 = $3) & ($2! = $4) {print $0 }}'
00007 31 00007 28
00002 04 00002 32
00010 94 00010 52
Others:
# Cat file1 file2 | sort | uniq-u
 
The answer on the third floor is wrong. what I want is
00002 31 32
00007 25 28
Sort file1> f1; sort file2> f2; join-j1 1 f1 f2 | awk '$2! = $3'
Or
Sort file1> f1; sort file2> f2; join-1 1-2 1 f1 f2 | awk '$2! = $3'
 
 
2. instance 2
# Cat fawk.
1 xiao 25 beijing 9000
2 liuwenjing 24 beijing 5000
3 weijianjun 29 shanghai 8000
4 wanmingyang 28 beijing 5000
5 tianzhiyu 25 beijing 5500
6 zhouhaoxing 23 beijing 5000
 
2.1 shows the full line of xiao, such as $2, or $2, which is equal to liu.
[Root @ store_2 awk] # awk '{if ($2 = "xiao") | ($2 = "liu") print $0} 'fawk. a
1 xiao 25 beijing 9000
 
2.3 display the rows of xiao or $2 including liu, such as $2
[Root @ store_2 awk] # awk '{if ($2 = "xiao") | ($2 ~ /Liu/) print $0} 'fawk.
1 xiao 25 beijing 9000
2 liuwenjing 24 beijing 5000
 
2.3 calculate how many rows of NR are displayed
[Root @ store_2 awk] # awk '{print $0} END {print "total number of rows:" NR} 'fawk.
1 xiao 25 beijing 9000
2 liuwenjing 24 beijing 5000
3 weijianjun 29 shanghai 8000
4 wanmingyang 28 beijing 5000
5 tianzhiyu 25 beijing 5500
6 zhouhaoxing 23 beijing 5000
Total number of rows: 6
2.4 display the last directory name of the current path
Echo $ PWD | awk-F/'{print $ NF }'
Echo $ PWD | awk-F/'{print NF}' # displays the number of columns or fields.
Echo $ PWD | awk-F/'{print NF-1}' # Calculation
2.4 replace functions
# Replacing xiao with hehe
[Root @ store_2 awk] # awk 'gsub (/xiao/, "hehe") 'fawk. a // $0, xiao replaces liu
1 hehe 25 beijing 9000
The same as sed's/xiao/hehe/'fawk. a, but all records are displayed.
2.5 length function
[Root @ store_2 awk] # awk '{print length ($4)}' fawk.
7
7
.....
2.6 split functions
Split (s, a, t) // t is the delimiter, s is the character, a is the array, a [1], a [2]...
 
2.7 calculate the size of all files in the directory
2.7.1 Single command
[Root @ store_2 awk] # ll | awk '{total + = $5} {print $0} END {print total}' # you can add multiple {}
Total 16
-Rw-r -- 1 root 354 10-29 fawk.
-Rwxr-xr-x 1 root 61 10-29 04-34 it. awk
415
 
2.7.2 programming
[Root @ store_2 awk] # cat it. awk
#! /Bin/awk-f
(Total + = $5)
END {print "total size:" total}
[Root @ store_2 awk] # ll |./it. awk
-Rw-r -- 1 root 354 10-29 fawk.
-Rwxr-xr-x 1 root 61 10-29 04-34 it. awk
Total: 415
 
3. instance 3
3.1 Delete all blank rows
Delete all blank lines in a file
Code ::
$ Awk 'NF> 0' test1.dat
One 123-321 234/22
Two 344-637 726/28 c
Three 273-287 287/97 d
Four 872-872 282/20 c
3.2 output an even number of rows of a file
Code ::
$ Awk 'NR % 2 = 0' test1.dat
Two 344-637 726/28 c
Four 872-872 282/20 c

3.3 The input value ranges from 1 to 100.
Code ::
$ Awk 'In in {for (I = 1; I <7; I ++) print int (101 * rand ())}'
24
29
85
15
59
19

3.5 output the number of bytes of all files in the local directory
Code ::
] $ Ls-l | awk '{x + = $5}; END {print x }'
15827
3.6 displays UID> 500 user records
[Root @ store_2 awk] # awk-F: '$3> 500 {print $0}'/etc/passwd
Nfsnobody: x: 65534: 65534: Anonymous NFS User:/var/lib/nfs:/sbin/nologin
You can also write as follows:
[Root @ store_2 awk] # awk-F: '{if ($3> 500) print $0}'/etc/passwd
Nfsnobody: x: 65534: 65534: Anonymous NFS User:/var/lib/nfs:/sbin/nologin
[Root @ store_2 awk] # awk-F: '{if ($3> 500) {print $0}'/etc/passwd
Nfsnobody: x: 65534: 65534: Anonymous NFS User:/var/lib/nfs:/sbin/nologin
 
The following is an incorrect syntax:
A. [root @ store_2 awk] # awk-F: '{$3> 500 print $0}'/etc/passwd
Awk: {$3> 500 print $0}
Awk: ^ syntax error
B. awk-F: '{$3> 500} {print $0}'/etc/passwd
Root: x: 0: 0: root:/bin/bash
Bin: x: 1: 1: bin:/sbin/nologin
Daemon: x: 2: 2: daemon:/sbin/nologin
.........
Author: Fengyun's blog"