CODEWITHSUNDEEP
regexawksedgrep
stuppie
stuppie

Reputation: 385

Print from Nth match to Mth match

How do I print from the nth match to the mth match in a file?

For example

>1
dfgsdrhsdtrh
>2
zdfrgsdh
>3
zdsfgadrh
>4
sdtrh
>5
drh

If I want the 2nd to the 4th match to the regexp '^>', including the Nth match and up to but not including the M+1th match. Yielding, for example:

>2
zdfrgsdh
>3
zdsfgadrh
>4
sdtrh

Upvotes: 1

Views: 80

Answers (3)

anubhava
anubhava

Reputation: 784938

Using gnu-awk you can use this awk:

awk -v RS='>' -v ORS='>' 'BEGIN{printf ">"} NR>5{exit} NR>2 && NR<=5' file
>2
zdfrgsdh
>3
zdsfgadrh
>4
sdtrh

Upvotes: 1

Jotne
Jotne

Reputation: 41446

Here is an awk solution:

awk -v RS=">" '$1>=2 && $1<=4 {$0=RS$0;gsub(/\n$/,"");print}' file
>2
zdfrgsdh
>3
zdsfgadrh
>4
sdtrh

It prints record from >2 to >4

Upvotes: 0

user557597
user557597

Reputation:

You could use the \K construct if supported. If not, just remove the \K and put capture
parenthesis around what comes after it. 

 #  (?m)(?:^>.*\r?\n(?:^(?!>).*\r?\n)*){1}\K(?:^>.*\r?\n(?:^(?!>).*\r?\n)*){3}

 (?m)                    # MULTI_LINE mode

 (?:                     # 0 to N-1
      ^ > .* \r? \n 
      (?:
           ^ 
           (?! > )
           .* \r? \n 
      )*
 ){1}                    # Do N-1 times

 \K                      # Disgard previous from match

 (?:                     # N to M+1
      ^ > .* \r? \n 
      (?:
           ^ 
           (?! > )
           .* \r? \n 
      )*
 ){3}                    # Do M+1-N times

Output: 

 **  Grp 0 -  ( pos 18 , len 40 ) 
>2
zdfrgsdh
>3
zdsfgadrh
>4
sdtrh

Upvotes: 0

Related Questions