The Problem

echo $PATH output is too long. I want to see it line by line.

First Attempt

➜  ~ echo $PATH | perl -E 'say $ARGV[0]'

➜  ~ echo $PATH | perl -E 'say'

why this does not work?

because piped content is passed in as <STDIN>

Second Attempt

pipe as STDIN

echo $PATH | perl -E 'say while <STDIN>'
echo $PATH | perl -E 'while (<STDIN>) { say for split /:/}'

The Right Way

echo $PATH | perl -nE 'say for split /:/'

Reference

-n causes Perl to assume the following loop around your program, which

makes it iterate over filename arguments somewhat like sed -n or

awk:

LINE:

while (<>) {

… # your program goes here

}

Note that the lines are not printed by default. See “-p” to have

lines printed. If a file named by an argument cannot be opened for

some reason, Perl warns you about it and moves on to the next file.

Also note that “<>” passes command line arguments to “open” in

perlfunc, which doesn’t necessarily interpret them as file names.

See perlop for possible security implications.

PS:

Another Solution with help from xargs

args to make pipe out to argv[0]

echo $PATH | xargs perl -E 'say for split /:/, $ARGV[0]'

Of Course, use perl directly with pipe works

perl -E 'say for split /:/ , $ENV{"PATH"}'