Keep only X number of entries of a file using a delimeter

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Keep only X number of entries of a file using a delimeter by choroba (Cardinal) on Oct 13, 2015 at 13:39 UTC
I imagine your input looks like this: `# Entry 1 ... # Entry 2 ...` [download] You can use $/ aka the Input record separator: `perl -pe 'BEGIN { $/ = "#" } exit if $. > 500' input-file` [download] $. contains the record number. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^2: Keep only X number of entries of a file using a delimeter by Anonymous Monk on Oct 13, 2015 at 14:19 UTC
Hi, interesting approach! Could you please re-write this to a "normal" script (i.e. not one-liner)?	[reply]
Re^3: Keep only X number of entries of a file using a delimeter by choroba (Cardinal) on Oct 13, 2015 at 14:26 UTC
Sure. Just add `-MO=Deparse` [download] before the switches. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re: Keep only X number of entries of a file using a delimeter by hdb (Monsignor) on Oct 13, 2015 at 13:39 UTC
Use a counter! Set `$/` to `"#"` to read the desired chunks. `use strict; use warnings; my $keep = 3; local $/="#"; while(<DATA>){ last unless $keep--; print; } __DATA__ 1 # 2 # 3 # 4 # 5` [download]	[reply] [d/l] [select]
Re^2: Keep only X number of entries of a file using a delimeter by SimonPratt (Friar) on Oct 15, 2015 at 15:48 UTC
You could also test `$.`, like so: `last if $. > 3;`	[reply] [d/l] [select]
Re^2: Keep only X number of entries of a file using a delimeter by Anonymous Monk on Oct 13, 2015 at 13:52 UTC
Thanks a bunch!	[reply]


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