$ cat t1.pl
#!/usr/bin/perl -p
BEGIN{$i=0}
s|
((?).*)
|''.$1.''|egs;
$ seq 1 10 | while read; do echo 'texttexxxxx
'; done | perl t1.pl
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
texttexxxxx
$