$ pwd
/home/ken/tmp

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' /usr/bin/perl
binary

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' file_perl
text

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' ./file_perl
text

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' ~/tmp/file_perl
text

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' ~ken/tmp/file_perl
text

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' ../tmp/file_perl
text

$ perl -E 'say +(qw{binary text})[-T $ARGV[0]]' ../../../usr/bin/perl
binary