How Perl one-liner for herding a group of sequences, out of its superset group, to be processed in a block of codes

The task fail done:

$ for i in {1..9} ;{ echo $i ;} |perl -pe 'my $s; if (/3/) {  while(1) { $s .= $_; print $s; last if (/7/) }  } '

to use Perl -pe option do output of string lines of:

1
2
3
4567
8
9

CodePudding user response：

Use this Perl one-liner:

for i in `seq 9` ; do echo $i; done | \
    perl -lne 'if ($_ == 3 .. $_ == 7) { push @a, $_; print @a if $_ == 7; next; } print;'
1
2
34567
8
9

The Perl one-liner uses these command line flags:
-e : Tells Perl to look for code in-line, instead of in a file.
-n : Loop over the input one line at a time, assigning it to $_ by default.
-l : Strip the input line separator ("\n" on *NIX by default) before executing the code in-line, and append it when printing.

SEE ALSO:
perldoc perlrun: how to execute the Perl interpreter: command line switches