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
将各个title 下边的合在一起 输出如下：
>a1
1
11
111
>a2
2
22
>b1
3
33
awk '/^>/&&!a[$1]++||!/^>/'
(可以改写成 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语句可以next代替，改写成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[$0]++' f1
>a1
>a2
>b1
2.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4157497&page=1#pid24299288
cat file:
aaaaaa
adada
adadadad
3a3a3
a3a3
a3s0
2a2a2a2a2
重复出现1至4次字符的行都输出，重复出现1至4次字符的结果应是
ababa
adadadad
3a3a3
a3s0
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++;l=asort(a)}a[l]<n' file
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$i]++}{for(i in a)print i,a[i]}' f5
a 6
a 3
d 2
a 4
d 4
a 2
3 3
a 2
3 2
a 1
0 1
s 1
3 1
a 4
2 5
（i为每行重复出现的字符，a[i]为每行中某个字符重复出现的次数）
awk -v n=5 -F '' '{delete a;for(i=1;i<=NF;i++)a[$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]为每行中某个字符重复出现的次数。i为每行中某个字符的数组下标值（每行去重后，每行有哪几个字符），如第一行只有a重复，去重后下标值为1；第二行中a、d重复，下标值为1、2；a3s0行没有重复，所以有下标值1、2、3、4，至于排序为何为4、1、2、3，可参考 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]为每行中某个字符重复出现的次数，所以a[len]<n表示取重复次数少于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 $AB
发现结果是以空格为分隔符
如何实现跟df -h一样的换行显示呢？
AB="$(df -h)"
echo "$AB"
4.
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4156330&page=1#pid24293665
有一个文件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
统计不同track name下的数目，结果如下：（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
（可以改写成next语句：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
(可以改写成next语句：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: 转义序列“\|”被当作单纯的“|”
2echo "a b|c"|awk -F'[ |]' '{print NF}'
3
awk -v RS='...'
这种写法是可以用少写一个，但不"规范"吧。可以少一个的原因是，最
后落单的那个\，经过 awk 的字符串解释后还是\，与\\的解释结果是一样的。
awk 'BEGIN{RS="...";}
写法就必须写够，一个也不能少。
$ 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"]"}'
出错
cat file：
123
123
{\
123
123
123
{\
1af
ewfwf
af
怎么才能用awk以{\为行分隔符来分割得到每一段的内容想要得到第一段
123
123
awk -vRS='{\\\\' 'NR==1'
6.
http://bbs.chinaunix.net/thread-3679733-1-1.html
字符串 'aaabcccaaabbbccc'，连续的字母作为一个子字符串，从左往右，去重复后，变为 'aaabcccbbb' ， awk或sed实现，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
如何得到以下结果:
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 ... 这样的方式是产生一个了shell子进程,自然子进程里的东西不能改变父进程的值
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
实现这样
（a=1且b=1）或者（c=1且d=1）成立时
echo pass
这样能用if实现么？
如何来嵌套？
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
二维数组
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没有的行
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代表你前面第一个\( \)里面的内容 \2代表第二个，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
根据第一行排序第二行
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 练习题（排序合并）
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"}'
