1.
http://bbs.chinaunix.net/thread-4157887-1-1.html
cat file:
>a1
1
>a1
11
>a1
111
>a2
2
>a2
22
>b1
3
>b1
33
將各個title 下邊的合在一起 輸出如下：
>a1
1
11
111
>a2
2
22
>b1
3
33
awk '/^>/&&!a[$1]++||!/^>/'
(可以改寫成 awk '/>/{if(!a[$0]++){print $0};next}1' )
awk '{if($0~/>/){m=$0}else{a[m]=a[m]"\n"$0}}END{for(i in a)print i,a[i]}'
（if else語句可以next代替，改寫成awk '{if(/>/){m=$0}else{a[m]=a[m]"\n"$0}}END{for(i in a)print i,a[i]}'）
awk '/>/{!a[$0]++;print}' f1
>a1
>a1
>a1
>a2
>a2
>b1
>b1
awk '/>/{print}' f1
>a1
>a1
>a1
>a2
>a2
>b1
>b1
awk '/>/{if(!a[$0]++)print $0}' f1
>a1
>a2
>b1
awk '/>/&&!a[$0]++' f1
>a1
>a2
>b1
2.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4157497&page=1#pid24299288
cat file:
aaaaaa
adada
adadadad
3a3a3
a3a3
a3s0
2a2a2a2a2
重複出現1至4次字符的行都輸出，重複出現1至4次字符的結果應是
ababa
adadadad
3a3a3
a3s0
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++;l=asort(a)}a[l]<n' file
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++}{for(i in a)print i,a[i]}' f5
a 6
a 3
d 2
a 4
d 4
a 2
3 3
a 2
3 2
a 1
0 1
s 1
3 1
a 4
2 5
（i爲每行重複出現的字符，a[i]爲每行中某個字符重複出現的次數）
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++;len=asort(a)}{for(i in a)print i,a[i]}' f5
1 6
1 2
2 3
1 4
2 4
1 2
2 3
1 2
2 2
4 1
1 1
2 1
3 1
1 4
2 5
（a[i]爲每行中某個字符重複出現的次數。i爲每行中某個字符的數組下標值（每行去重後，每行有哪幾個字符），如第一行只有a重複，去重後下標值爲1；第二行中a、d重複，下標值爲1、2；a3s0行沒有重複，所以有下標值1、2、3、4，至於排序爲何爲4、1、2、3，可參考 awk 'BEGIN{s="a3s0";split(s,a,"");len=asort(a);for(i in a)print i,a[i]}'
4 s
1 0
2 3
3 a）
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++;len=asort(a)}{print a[len]}' f5
6
3
4
3
2
1
5
（a[len]爲每行中某個字符重複出現的次數，所以a[len]<n表示取重複次數少於n的行）
3.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4157298&page=1#pid24298104
df -h
/dev/sda2 49G 21G 26G 45% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 193M 34M 150M 19% /boot
AB=`df -h`
echo $AB
發現結果是以空格爲分隔符
如何實現跟df -h一樣的換行顯示呢？
AB="$(df -h)"
echo "$AB"
4.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4156330&page=1#pid24293665
有一個文件file1：（tab分隔）
track name=STRINGENT_LT_1KB
chr3 23232 asdbaskjdb
chr3 32434 daffsf
chr5 43131 dkfjkdjgkdjgk
chr6 4574857 wejwe
chr7 11313 sjdjsgd
chr8 2323 lskdkss
track name=STRINGENT_HIGH_SCORE
chr1 1212123 fkekfhd
chr2 2322342 ererer
chr2 43444 sdsdsd
chr3 454545 dkfjdkjfk
chr5 343434 qsadjhdjh
track name=STRINGENT_LT_332KB
track name=STRINGENT_LOW_SCORE
chr7 2323232 sdsdsdaaa
chr10 223232 dssdsds
chr19 677675 dlkslk
統計不同track name下的數目，結果如下：（tab分隔）
track name=STRINGENT_LT_1KB：6
track name=STRINGENT_HIGH_SCORE：5
track name=STRINGENT_LT_332KB：0
track name=STRINGENT_LOW_SCORE：3
awk '{if(/^t/){if(NR>1)print s":"n;n=0;s=$0}else n++}END{print s":"n}' f8
（可以改寫成next語句：awk '/^t/{if(NR>1)print s":"n;n=0;s=$0;next}{n++}END{print s":"n}' f8）
awk '{if(/track/){m=$0}else i++;print m,i}' f8
track name=STRINGENT_LT_1KB
track name=STRINGENT_LT_1KB 1
track name=STRINGENT_LT_1KB 2
track name=STRINGENT_LT_1KB 3
track name=STRINGENT_LT_1KB 4
track name=STRINGENT_LT_1KB 5
track name=STRINGENT_LT_1KB 6
track name=STRINGENT_HIGH_SCORE 6
track name=STRINGENT_HIGH_SCORE 7
track name=STRINGENT_HIGH_SCORE 8
……
awk '{if(/track/){m=$0;i=0}else i++;print m,i}' f8
track name=STRINGENT_LT_1KB 0
track name=STRINGENT_LT_1KB 1
track name=STRINGENT_LT_1KB 2
track name=STRINGENT_LT_1KB 3
track name=STRINGENT_LT_1KB 4
track name=STRINGENT_LT_1KB 5
track name=STRINGENT_LT_1KB 6
track name=STRINGENT_HIGH_SCORE 0
track name=STRINGENT_HIGH_SCORE 1
track name=STRINGENT_HIGH_SCORE 2
track name=STRINGENT_HIGH_SCORE 3
track name=STRINGENT_HIGH_SCORE 4
track name=STRINGENT_HIGH_SCORE 5
……
awk '{if(/^t/){m=$0;i=0}else i++}END{print m,i}' f8
track name=STRINGENT_LOW_SCORE 3
awk '{if(/^t/){m=$0;a[m]=0}else a[m]++}END{print m,a[m]}' f8
track name=STRINGENT_LOW_SCORE 3
awk '{if(/^t/){m=$0;a[m]=0}else a[m]++}END{for(i in a){print i":"a[i]}}' f8
(可以改寫成next語句：awk '/^t/{m=$0;a[m]=0;next}{a[m]++}END{for(i in a){print i":"a[i]}}' f8)
track name=STRINGENT_LT_1KB:6
track name=STRINGENT_LT_332KB:0
track name=STRINGENT_HIGH_SCORE:5
track name=STRINGENT_LOW_SCORE:3
awk '{if(/^t/){if(NR>1)print s;s=$0}}' f8
track name=STRINGENT_LT_1KB
track name=STRINGENT_HIGH_SCORE
track name=STRINGENT_LT_332KB
awk '{if(/^t/){if(NR>1)print s;s=$0;print s}}' f8
track name=STRINGENT_LT_1KB
track name=STRINGENT_LT_1KB
track name=STRINGENT_HIGH_SCORE
track name=STRINGENT_HIGH_SCORE
track name=STRINGENT_LT_332KB
track name=STRINGENT_LT_332KB
track name=STRINGENT_LOW_SCORE
5.
http://bbs.chinaunix.net/thread-4155608-2-1.html
echo "a b|c"|awk -F' |\\|' '{print NF}'
3echo "a b|c"|awk -F' |\|' '{print NF}'
awk: 警告: 轉義序列“\|”被當作單純的“|”
2echo "a b|c"|awk -F'[ |]' '{print NF}'
3
awk -v RS='...'
這種寫法是可以用少寫一個，但不"規範"吧。可以少一個的原因是，最
後落單的那個\，經過 awk 的字符串解釋後還是\，與\\的解釋結果是一樣的。
awk 'BEGIN{RS="...";}
寫法就必須寫夠，一個也不能少。
$ echo -E '\\\'
\\\$ echo|awk -v v='\\\' '{print "["v"]"}'
[\\]$ echo|awk -v v='\\\\' '{print "["v"]"}'
[\\]$ echo|awk -v v='\' '{print "["v"]"}'
[\]$ echo|awk -v v='\\' '{print "["v"]"}'
[\]$ echo|awk 'BEGIN{v="\\";}{print "["v"]"}'
[\]$ echo|awk 'BEGIN{v="\\\";}{print "["v"]"}'
出錯
cat file：
123
123
{\
123
123
123
{\
1af
ewfwf
af
怎麼才能用awk以{\爲行分隔符來分割得到每一段的內容想要得到第一段
123
123
awk -vRS='{\\\\' 'NR==1'
6.
http://bbs.chinaunix.net/thread-3679733-1-1.html
字符串 'aaabcccaaabbbccc'，連續的字母作爲一個子字符串，從左往右，去重複後，變爲 'aaabcccbbb' ， awk或sed實現，不使用管道。
awk -F '' '{while(i++<=NF){s=s$i;if($i!=$(i+1)){if(!a[s]++)printf s;s=""}}}'
awk -F'ccc' '{sub(/[a]+/,"",$2);print $1FS$2}'
7.
seq 9
1
2
3
4
5
6
7
8
9
如何得到以下結果:
1 2 3
2 3 4
3 4 5
4 5 6
5 6 7
6 7 8
7 8 9
8 9
seq 9|awk '{a[NR]=$0}END{for(i=1;i<NR;i++)print a[i],a[i+1],a[i+2]}'
seq 9 | awk '{b=($1+1<=9)?$1+1:" ";c=($1+2<=9)?$1+2:" "; print $1" "b" "c}'
seq 9|awk 'NR==1{a=$1};NR==2{b=$1};NR>2{print a,b,$1;a=b;b=$1}END{print a,b}'
8.
http://bbs.chinaunix.net/thread-4154751-1-1.html
[root@localhost ~]# a=1
[root@localhost ~]# while read num ; do a=$num ; done < <(seq 5) ; echo $a
5
[root@localhost ~]# for num in $(seq 5) ; do a=$num ; done ; echo $a
5
seq 5 | while ... 這樣的方式是產生一個了shell子進程,自然子進程裏的東西不能改變父進程的值
9.
http://bbs.chinaunix.net/thread-4154600-1-1.html
awk '/<frame name="mainFrame" src="/{print a[match($0,/<frame name="mainFrame" src="\/([^"]*)".*/,a)]}'
grep -Po '(?<=name="mainFrame" src=")[^"]+'
awk -F '[=" ]+' -v RS=">" '/"mainFrame" src="/{print $6}'
10.
http://bbs.chinaunix.net/thread-4154603-1-1.html
實現這樣
（a=1且b=1）或者（c=1且d=1）成立時
echo pass
這樣能用if實現麼？
如何來嵌套？
a=1; b=1; c=0; d=0;if [ $a -eq 1 ] && [ $b -eq 1 ];then echo pass;elif [ $c -eq 1 ] && [ $d -eq 1 ];then echo pass;fi
a=1; b=1; c=0; d=0; if (((a==1 && b==1 )||(c==1 && d ==1)));then echo pass;fi
awk 'BEGIN{a=1;b=1;c=0;d=1;if(((a==1&&b==1)||(c==1&&d==1))){print "pass"}else{print "。。"}}'
awk 'BEGIN{a=1; b=1; c=0; d=0;if(a==1&&b==1){print "pass"}else if(c==1&&d==1){print "pass"}else{print "。。"}}'
if [[ ($a = 1 && $b = 1) || ($c = 1 && $d = 1) ]];then
echo True
else
echo False
fi
11.
http://bbs.chinaunix.net/thread-4154531-3-1.html
awk 'm~/==/&&/^\s*$/{print m}{m=$0}'
12.
http://bbs.chinaunix.net/thread-4154504-1-1.html
grep -vf B A
awk 'NR==FNR{a[$0];next}{for(i in a){if(match($0,i)>0)next}print}' B A
awk 'NR==FNR{a[$0];next}{for(i in a)if(index($0,i))next}1' B A
awk 'FNR==NR{k=k?k"|"$0:$0;next}$0!~k{print}' B A
(awk '{k=k?k"|"$0:$0}END{print k}' B
Now|We|ment)
13.
http://bbs.chinaunix.net/thread-4154469-1-1.html
二維數組
awk 'BEGIN{for(i=1;i<=3;i++)for(j=1;j<=4;j++)a[i,j]=i*j;for(x in a){split(x,b,SUBSEP);print b[1]"*"b[2]"="a[x]}}'
找出文件A有文件B沒有的行
awk 'BEGIN{for(i=1;i<=3;i++){for(j=1;j<=4;j++){s=s"R"i"C"j;print s}}}'
或者awk 'BEGIN{for(i=1;i<=3;i++)for(j=1;j<=4;j++)print "R"i"C"j}'
awk 'BEGIN{for(i=1;i<=3;i++)for(j=1;j<=4;j++)a["R"i"C"j];for(i in a)print i}'
awk '{for(i=1;i<=3;i++)for(j=1;j<=4;j++)a["R"i"C"j]}END{for(i in a)print i}' file
awk 'BEGIN{for(i=1;i<=3;i++){for(j=1;j<=4;j++){s="R"i"C"j;print s>"file"}}}'
awk 'NR==FNR{a[$2];next}{for(i in a){if($0==i)next}print}’
14.
http://bbs.chinaunix.net/thread-4153934-1-1.html
awk '{ORS=NR%2?"\n":" "}1'
awk 'NR==1{print;next}NR%2==0{lastline=$0;next}{print lastline,$0}'
awk 'NR%2==0{m=$0}NR%2==1{print m,$0}'
awk 'NR==1{print}NR%2==0{x=NR;m=$0}x{getline s;print m,s}'
awk 'NR==1{print}NR%2==0{x=NR;m=$0}x&&NR-x==1{print m,$0}'
awk 'NR==1{print}{a[NR]=$0}END{for(i=1;i<=NR;i++){if(i%2==0)print a[i],a[i+1]}}'
15.
http://bbs.chinaunix.net/thread-4150372-1-1.html
\1代表你前面第一個\( \)裏面的內容 \2代表第二個，以此例推
awk --re-interval 'NR==1{a=gensub(/.*(.{10})/,"\\1",1);print a+0}'
awk -F '' '{m=substr($0,NF-9,NF);gsub(/0+/,"",m);print m}'
16.
http://bbs.chinaunix.net/thread-4150043-1-1.html
awk '{a[$1]=$2;b[$1]=$1}END{for(i=1;i<=asort(b,c);i++)print b[c[i]],a[b[c[i]]],i%3==1?++n:n}'
cat file:
1 a
3 s
2 f
5 g
7 j
4 t
9 r
6 w
8 l
根據第一行排序第二行
awk '{a[$1]=$2}END{for(i=1;i<=NR;i++)print i,a[i]}'
awk '{a[$1]=$2}END{for(i=1;i<=asort(a,c);i++)print i,a[i]}'
$ cat file
aaa 125
ddd 123
bbb 128
ccc 120
$ awk '{a[$2]=$0}END{for(i=1;i<=asort(a);i++)print a[i]}' file
aaa 125
bbb 128
ccc 120
ddd 123
$ awk '{a[$2]=$0}END{for(i=1;i<=asorti(a,b);i++)print a[b[i]]}' file
ccc 120
ddd 123
aaa 125
bbb 128
echo "8 11111 9" | awk '{split($0,a," ");for(i=1;i<=asort(a,c);i++)print i,a[i],c[i]}'
1 8 8
2 11111 9
3 9 11111
echo "8 11111 9" | awk '{split($0,a," ");for(i=1;i<=asort(a);i++)print i,a[i],c[i]}'
1 8
2 9
3 11111
echo "8 11111 9" | awk '{split($0,a," ");for(i=1;i<=asort(a,c);i++)print i,a[2],c[2]}'
1 11111 9
2 11111 9
3 11111 9
17.
http://bbs.chinaunix.net/thread-4149019-1-1.html
var="'(]\\{}\$\""
18.
http://bbs.chinaunix.net/thread-1393874-1-1.html
#! /bin/sh
A=B echo $A
echo $A
19.
http://bbs.chinaunix.net/thread-4148647-1-1.html
awk '/ve/||(sub($2,$2 FS $NF) && NF--)' OFS='\t'
awk '/ap/{for(i=1;i<=NF;i++){if(i==3)printf $NF"\t"$i"\t";else if($i==$NF)print "";else{printf $i"\t"}}next}1'
20.
http://blog.chinaunix.net/uid-20778583-id-4247874.html
awk 'NR==FNR{a[$1" "$2" "$3]=$1;b[$1]++}NR>FNR{counter=0;for(i in a)if($1==a[i]){split(i,m," ");i || $2>m[3] || (m[2]==$2 && m[3]==$3))counter++}print NR,counter}' f1 f1
awk 'NR==FNR{a[$1" "$2" "$3]=$1;b[$1]++}NR>FNR{counter=0;for(i in a){if($1==a[i]){split(i,m," ");] || $2>m[3] || ( m[2]==$2 && m[3]==$3))counter++;else next;if(counter == b[$1])print $0}}}' f1 f1
21.
http://bbs.chinaunix.net/thread-3620300-1-1.html
awk '{if($1==x){s=s","$2}else{if(NR>1){print s}s=$1"\t"$2}x=$1}END{print s}'
awk '{x[$1]=length(x[$1])?x[$1]","$2:$2}END{for(i in x)print i"\t"x[i]}'
awk '{x[$1]=length(x[$1])?x[$1]","$2:$2;len=asorti(x,b)}END{for(i=1;i<=len;i++)print b[i],x[b[i]]}' f5
awk '/track/{x=NR;a[x]=$0}x{print x,NR,a[x],NR-x}'
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4156330&page=1#pid24396455
7720 98
7720 99
7720 218
7720 219
7720 220
awk '{a[$1]=$2}{printf a[$1]","}'
awk -v RS='7720' '{printf ","$1}'
awk '{x=$1;if($1==x){s=s","$2}}END{print x,s}'
awk '{if($1==x){s=s","$2}else{if(NR>1){print s}s=$1"\t"$2}x=$1}END{print s}'
awk '{if($1==x){if($2==y+1)s=s"-"$2;else s=s","$2}else{if(NR>1){print s}s=$1"\t"$2}x=$1;y=$2}END{gsub(/-[^,]*-/,"-",s);print s}'
22.
http://bbs.chinaunix.net/thread-4119434-1-1.html 練習題（排序合併）
awk '{m=gensub(/([^0-9]+).*/,"\\1",1,$2);n=gensub(/[^0-9]+(.*)/,"\\1",1,$2);t=$1" "sprintf("%s%10[t]=$1;b[t]=m;c[t]=n}END{for(i=0;i++<asorti(c,d);){print d[i],a[d[i]]}}'
apple cat 12 apple
apple cat 106 apple
apple cat 107 apple
apple cat 108 apple
apple cat 109 apple
apple cat 123 apple
apple cat 125 apple
pear dog 11 pear
pear dog 101 pear
pear dog 103 pear
pear dog 104 pear
pear dog 105 pear
pear mouse 106 pear
pear mouse 107 pear
pear mouse 108 pear
pear mouse 109 pear
pear mouse 123 pear
pear mouse 125 pear
awk '{m=gensub(/([^0-9]+).*/,"\\1",1,$2);n=gensub(/[^0-9]+(.*)/,"\\1",1,$2);t=$1" "sprintf("%s%10s",m,n);a[t]=$1;b[t]=m;c[t]=n}END{for(i=0;i++<asorti(c,d);){if(!k)printf "%s: ",a[d[i]]}}'
awk '{m=gensub(/([^0-9]+).*/,"\\1",1,$2);n=gensub(/[^0-9]+(.*)/,"\\1",1,$2);t=$1" "sprintf("%s%10s",m,n);a[t]=$1;b[t]=m;c[t]=n}END{for(i=0;i++<asorti(c,d);){if(!k)printf "%s: ",a[d[i]];if(k&&k!=a[d[i]]){printf "%s\n%s: ",s,a[d[i]];s=""}}}'
23.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4147474
awk '{a[$1];for(i=1;i++<NF;)b[$1,i]=b[$1,i]!=""?b[$1,i]"/"$i:$i}END{for(i in a){printf i;for(j=1;j++<NF;)printf " "b[i,j];print ""}}'
awk '{if(a[$1]){split(a[$1],b," ");a[$1]=$1" "b[2]"/"$2" "b[3]"/"$3" "b[4]"/"$4}else{a[$1]=$0}}END{l=asort(a);for(i=1;i<=l;i++)print a[i]}' file
24.
http://bbs.chinaunix.net/thread-4145403-1-1.html
awk -F '' '{if($3~4)print $0>"a";else print$0>"b"}' f5
awk -F '' '$3~4{print $0>"e"}$3~5{print$0>"f"}' f5
awk '/^..4/{print $0>"g"}/^..5/{print$0>"h"}' f5
awk '{m=substr($0,3,1);if(m==4)print $0>"c";else{print $0>"d"}}' f5
awk '{print >substr($0,3,1)".txt"}'