A somewhat different approach to the problem--it strikes a balance between slurping the file and processing it line by line--setting $/ as a 'boundary marker' and using -n to take care of the file handling. You just attach your code at the bottom and process the %ids hash as you need to.

Caveats: It doesn't validate the format of the input file by cross-checking the end of block with the start. Testing is minimal in the absence of more information regarding the file format/content, and there are too many possible variations to try and guess. 

#! perl -nslw
use vars qw[%ids];
use strict;
BEGIN{$/="\nchecking";}

    if ( m[<(NT-Development_\d{10}_FULL)>.*?(media does not exist)?\Z]
+s ) {
        $ids{$1} = defined $2 ? 'missing' : 'ok';
    }
}{ #! terminate implied (perl -n) while loop and start continue block
#! process hash here.
    print "$_ was $ids{$_}" for sort keys %ids;

[download]

sample usage

 7:59:54.25 C:\test>type junk
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog
checking image file <NT-Development_1024371283_FULL>
>copy 1 frag 1 media CC0202 host netbackup2: media does not exist
>copy 1 frag 2 media CC0202 host netbackup2: media does not exist
>copy 1 frag 3 media CC0202 host netbackup2: media does not exist
>copy 1 frag 4 media CC0202 host netbackup2: media does not exist
>copy 1 frag 5 media CC0202 host netbackup2: media does not exist
checking files file <NT-Development_1024371283_FULL.f>
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog
checking image file <NT-Development_1024371284_FULL>
>copy 1 frag 5 media CC0202 host netbackup2:
checking files file <NT-Development_1024371284_FULL.f>
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog
Sir! The pedants are regrouping. Sir! The pedants are regrouping.
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog
checking image file <NT-Development_1024371285_FULL>
>copy 1 frag 1 media CC0202 host netbackup2: media does not exist
>copy 1 frag 5 media CC0202 host netbackup2: media does not exist
checking files file <NT-Development_1024371285_FULL.f>
the quick brown fox jumps over the lazy dog the quick brown fox jumps 
+over the lazy dog

 7:59:59.93 C:\test>test junk
NT-Development_1024371283_FULL was missing
NT-Development_1024371284_FULL was ok
NT-Development_1024371285_FULL was missing

[download]

Examine what is said, not who speaks.

The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

In reply to Re: How to act upon lines between two other lines in file? by BrowserUk
in thread How to act upon lines between two other lines in file? by blink

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