perl -i.one -le 'chomp( my @cinfo= <> ); $cinfo[1]=0; print @cinfo' *.
+txt
perl -i.one -e 'my @cinfo= <>; $cinfo[1]= "0\n"; print @cinfo' *.txt
perl -i.one -nle 'print 2==$. ? 0 : $_' *.txt
perl -i.one -ple '$_= 0 if 2==$.' *.txt
perl -i.one -pe '$_= "0\n" if 2==$.' *.txt
[download]

But if you are on Win32, you instead could use:

perl -i.one -le "BEGIN{@ARGV= glob(@ARGV)} chomp( my @cinfo= <> ); $ci
+nfo[1]= 0; print @cinfo" *.txt
perl -i.one -e "BEGIN{@ARGV= glob(@ARGV)} my @cinfo= <>; $cinfo[1]= 0.
+$/; print @cinfo" *.txt
perl -i.one -nle "BEGIN{@ARGV= glob(@ARGV)} print 2==$. ? 0 : $_" *.tx
+t
perl -i.one -ple "BEGIN{@ARGV= glob(@ARGV)} $_= 0 if 2==$." *.txt
perl -i.one -pe "BEGIN{@ARGV= glob(@ARGV)} $_= 0.$/ if 2==$." *.txt
[download]

But there are lots of other ways you could do it as well.

Didn't we already have that question in this node?

"Perl makes the fun jobs fun
and the boring jobs bearable" - me