Perl：当我从命令行运行“perl”时没有任何反应

Question

If I run perl by itself from the linux command line, nothing happens. I see the cursor move down a line and if I enter print "Hello, world"; , still nothing happens. Is there anything I can input from the command line from here? I know that you can run perl -e 'print "Hello, world"'; and how to create a perl script. Just wondering why running perl by itself does nothing.

Answer 1

Type the following:

$ perl
print "Hello World\n";
Ctrl-D
Hello World
$

That's last line is you holding down the Control key and pressing D . Not typing Ctrl-D .

If you type stty -a , you'll see that Ctrl-D is he EOF character. That's Perl reading in a file from STDIN. Is that what you want?

Answer 2

On my system (Windows, cmd shell) if I just type perl it starts to read code from STDIN, and when I hit end of file Ctrl-Z, it executes the code. As demonstrated here:

C:\perl>perl
$a = "asd";
print "\$a = '$a'";
^Z
$a = 'asd'
C:\perl>perl
use Data::Dumper;
print Dumper [ 3.14 ];
^Z
$VAR1 = [
          '3.14'
        ];

This is handy, because normally I can't use double quotes in the cmd shell without quoting issues.

Answer 3

Run perl by itself in Linux command line, perl will wait for your input, as exampled by the answer given by @david-w

If you want a interactive Perl environment, you can start perl in debugging mode by perl -d -e 42 , or install Perl Shell(psh) .

Run perldoc perlrun and perldoc perldebug for further details.

Answer 4

Try:

perl -e "print 'Hello World';"

Otherwise, just entering perl doesn't really do anything. (That I know of, mines does the same as yours)

Answer 5

I think you're looking for perl shell.. aka PSH

https://metacpan.org/pod/distribution/psh/doc/psh.pod