復(fù)習(xí)

• awk 中使用外部shell變量

awk的-v選項(xiàng)用于定義參數(shù)，有多少個(gè)變量需要賦值，就需要多少個(gè)-v選項(xiàng)严嗜。
腳本命令如下：

#! /bin/bash
sort -n filename |awk -F ':' '{print $1}'|uniq >id.txt
for id in `cat id.txt`; do
        echo "[$id]"
        awk -v id2=$id -F ':' '$1==id2 {print $2}' filename  // 另外的方式為: awk -F ':' '$1=="'id'" {print $2}' filename  
done

運(yùn)行腳本后顯示如下：

[root@minglinux-01 sbin]# cat filename 
1:aaaaaaaa
2:bbbbbbbbbb
3:cccccc
1:qqqqqqq
2:rrrrrrrr
[root@minglinux-01 sbin]# sh test.sh 
[1]
aaaaaaaa
qqqqqqq
[2]
bbbbbbbbbb
rrrrrrrr
[3]
cccccc

• awk 合并一個(gè)文件

[root@minglinux-01 ~]# cat 1.txt 
1 a 
2 b
3 c
4 d
[root@minglinux-01 ~]# cat 2.txt 
1 A
2 B 
3 C
4 D
5 E
[root@minglinux-01 ~]# cat 1.txt 2.txt 
1 a 
2 b
3 c
4 d
1 A
2 B 
3 C
4 D
5 E
[root@minglinux-01 ~]# awk '{print NR}' 1.txt 2.txt 
1
2
3
4
5
6
7
8
9
[root@minglinux-01 ~]# awk '{print FNR}' 1.txt 2.txt 
1
2
3
4
1
2
3
4
5
[root@minglinux-01 ~]# awk 'NR==FNR{a[$1]=$2}NR>FNR{print $0,a[$1]}' 1.txt 2.txt 
1 A a
2 B b
3 C c
4 D d
5 E 

上例中NR表示讀取的行數(shù)倒淫， FNR表示讀取的當(dāng)前行數(shù)碉咆，通過(guò)運(yùn)行awk '{print NR,FNR}' 1.txt 2.txt的結(jié)果可以看出抖韩。所以NR==FNR 就表示讀取1.txt的時(shí)候，而 NR>FNR表示讀取2.txt的時(shí)候疫铜。

• 把一個(gè)文件多行連接成一行

3種方法示例命令如下：

[root@minglinux-01 ~]# cat 3.txt 
a
b
c
d
e
f
[root@minglinux-01 ~]# a=`cat 3.txt`;echo $a
a b c d e f
[root@minglinux-01 ~]# awk '{printf("%s ",$0)}' 3.txt;echo ""    \\%s指定字符串的輸出內(nèi)容格式茂浮，echo "" 的作用是換行。
a b c d e f 
[root@minglinux-01 ~]# cat 3.txt |xargs 
a b c d e f

把3.txt中每行的字母用“+”連接起來(lái)：

[root@minglinux-01 ~]# cat 3.txt |xargs|sed 's/ /+/g'
a+b+c+d+e+f
[root@minglinux-01 ~]# awk '{printf("%s+",$0)}' 3.txt;echo""
a+b+c+d+e+f+

• awk中g(shù)sub函數(shù)的使用

awk 'gsub(/www/,"abc")' /etc/passwd // passwd文件中把所有root替換為abc
awk -F ':' 'gsub(/www/,"abc",$1) {print $0}' /etc/passwd // 替換$1中的root為abc

[root@minglinux-01 ~]# awk 'gsub(/root/,"abc")' /etc/passwd 
abc:x:0:0:abc:/abc:/bin/bash
operator:x:11:0:operator:/abc:/sbin/nologin
[root@minglinux-01 ~]# awk -F ':' 'gsub(/root/,"abc",$1) {print $0}' /etc/passwd
abc x 0 0 root /root /bin/bash

• awk 截取指定多個(gè)域?yàn)橐恍?/h5>

[root@minglinux-01 ~]# cat test.sh 
#!/bin/bash
for i in `seq 1 7`
do 
 awk -F ':' -v a=$i '{printf $a " "}' /etc/passwd
 echo
done
sh test.sh 
root bin daemon adm lp sync shutdown halt mail operator games ftp nobody systemd-network dbus polkitd sshd postfix ming test10 user11 ntp 
x x x x x x x x x x x x x x x x x x x x x x 
0 1 2 3 4 5 6 7 8 11 12 14 99 192 81 999 74 89 1001 1010 1005 38 
0 1 2 4 7 0 0 0 12 0 100 50 99 192 81 998 74 89 1002 1003 1004 38 
root bin daemon adm lp sync shutdown halt mail operator games FTP User Nobody systemd Network Management System message bus User for polkitd Privilege-separated SSH      
/root /bin /sbin /var/adm /var/spool/lpd /sbin /sbin /sbin /var/spool/mail /root /usr/games /var/ftp / / / / /var/empty/sshd /var/spool/postfix /home/ming /home/test10 /home/user11 /etc/ntp 
/bin/bash /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /bin/sync /sbin/shutdown /sbin/halt /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /sbin/nologin /bin/bash /bin/bash /bin/bash /sbin/nologin

• 過(guò)濾兩個(gè)或多個(gè)關(guān)鍵詞

[root@minglinux-01 ~]# cat b.txt 
letme
karsa
xiaohu 
uzi
ming
.....
mlxg
uzi
lose 
s8
[root@minglinux-01 ~]# grep -E 'uzi|ming' b.txt 
uzi
ming
uzi
[root@minglinux-01 ~]# egrep 'uzi|ming' b.txt 
uzi
ming
uzi
[root@minglinux-01 ~]# awk '/uzi|ming/' b.txt 
uzi
ming
uzi

• 用awk生成以下結(jié)構(gòu)文件

用awk編寫(xiě)生成以下結(jié)構(gòu)文件的程序壳咕。( 最后列使用現(xiàn)在的時(shí)間席揽，時(shí)間格式為YYYYMMDDHHMMSS) 各列的值應(yīng)如下所示，每增加一行便加1囱井，共500萬(wàn)行驹尼。
1,1,0000000001,0000000001,0000000001,0000000001,0000000001,0000000001,2005100110101
2,2,0000000002,0000000002,0000000002,0000000002,0000000002,0000000002,2005100110101

[root@minglinux-01 ~]# awk 'BEGIN{for(i=1;i<=5000000;i++)printf("%d,%d,%010d,%010d,%010d,%010d,%010d,%010d,%d\n",i,i,i,i,i,i,i,i,strftime("%Y%m%d%H%M%S"))}'
1,1,0000000001,0000000001,0000000001,0000000001,0000000001,0000000001,20181022230158
2,2,0000000002,0000000002,0000000002,0000000002,0000000002,0000000002,20181022230158
3,3,0000000003,0000000003,0000000003,0000000003,0000000003,0000000003,20181022230158
4,4,0000000004,0000000004,0000000004,0000000004,0000000004,0000000004,20181022230158
5,5,0000000005,0000000005,0000000005,0000000005,0000000005,0000000005,20181022230158
6,6,0000000006,0000000006,0000000006,0000000006,0000000006,0000000006,20181022230158
7,7,0000000007,0000000007,0000000007,0000000007,0000000007,0000000007,20181022230158
8,8,0000000008,0000000008,0000000008,0000000008,0000000008,0000000008,20181022230158
9,9,0000000009,0000000009,0000000009,0000000009,0000000009,0000000009,20181022230158
10,10,0000000010,0000000010,0000000010,0000000010,0000000010,0000000010,20181022230158
......

• awk用print打印單引號(hào)

awk 'BEGIN{print "a'"'"'s"}' //不用脫義，就多寫(xiě)幾個(gè)單引號(hào)庞呕、雙引號(hào)
awk 'BEGIN{print "a'''s"}' //用脫義新翎，脫義的是單引號(hào)
awk 'BEGIN{print "a"s"}' //用脫義，脫義的是雙引號(hào)

[root@minglinux-01 ~]# awk 'BEGIN{print "a'"'"'s"}'
a's
[root@minglinux-01 ~]# awk 'BEGIN{print "a'\''s"}' 
a's
[root@minglinux-01 ~]# awk 'BEGIN{print "a\"s"}'
a"s

• 把兩個(gè)文件中相同的行合并成一行

[root@minglinux-01 ~]# cat 1.txt 
a b c
1 2 3
4 5 6
[root@minglinux-01 ~]# cat 2.txt 
c b a
3 2 1
6 5 4
[root@minglinux-01 ~]# paste 1.txt 2.txt 
a b c   c b a
1 2 3   3 2 1
4 5 6   6 5 4

還可以用-d選項(xiàng)在兩個(gè)文件連接處用一個(gè)指定的字符連接住练，示例命令如下：

[root@minglinux-01 ~]# paste -d '+' 1.txt 2.txt 
a b c+c b a
1 2 3+3 2 1
4 5 6+6 5 4