The shell quoting rules are different between Windows and Linux/UNIX. Within double quotes (") the $ sign is significant to the Linux/UNIX shell. Try:
>perl -Mntheory=:all -nE 'chomp; say is_prime($_);' input.txt
The argument for the -e flag is surrounded with " on Windows, but with ' on Linux/UNIX. Quoting rules therefore are different in the body of the script provided via -e, which led iirc to the q() family of operators (see perlop)
update: the _ identifier is set in the shell to the last argument of the previous command, so $_ is set to input.txt which is interpolated into the program string passed to perl via -e as the expression of concatenation of two barewords:
qwurx [shmem] ~> perl -E "say '$_'" foo.bar
qwurx [shmem] ~> perl -E "say '$_'" foo.bar
foo.bar
qwurx [shmem] ~> perl -E "say $_" foo.bar
foobar
This is a dangerous thing, if the last argument of the previous line happens to contain metacharacters, e.g.
qwurx [shmem] ~> echo '`ls -l /dev/null`'
`ls -l /dev/null`
qwurx [shmem] ~> perl -E "say $_"
crw-rw-rw- 1 root root 1, 3 Nov 27 11:02 /dev/null
qwurx [shmem] ~> perl -MO=Deparse -E "say $_"
use feature 'current_sub', 'evalbytes', 'fc', 'say', 'state', 'switch'
+, 'unicode_strings', 'unicode_eval';
say say(say(`ls -l /dev/null`));
-e syntax OK
so don't do that.
perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.