Why do I get 'use: command not found' when I run my Perl script?

Question

I'm new to Perl. And I have used following code from one forum to connect to one of the server. but throwing error messages

[root@Cus]# cat tt.pl
#!/usr/bin/perl
use Net::Telnet;
$telnet = new Net::Telnet ( Timeout=>2, Errmode=>'die');
$telnet->open('10.0.0.28');
$telnet->waitfor('/login:/');
$telnet->print('administrator');
$telnet->waitfor('/Password:/');
$telnet->print('test');
$telnet->waitfor('/switch8-12>/');
$telnet->print('whoamI');
$output=$telnet->waitfor('/switch8-12>/');
print $output;

But throwing following error messages.

[root@Cus]# ./tt.pl
./tt.pl: line 3: use: command not found
./tt.pl: line 4: syntax error near unexpected token `('
./tt.pl: line 4: `$telnet = new Net::Telnet ( Timeout=>2, Errmode=>'die');'

Answer 1

My guess is that you're using a weird flavour of unix that doesn't respect the #! line, and is trying to run the script via the shell instead of via perl.

Another reason why this might happen is if tt.pl starts with a blank line. The #! must appear at the very start of the file.

Try running perl tt.pl and see what happens.

Answer 2

I don't see these lines at the top of your script, which are essential for all perl modules and scripts:

use strict;
use warnings;

You didn't say which environment this is running in -- are you using bash on linux? Whatever shell you are using does not understand the shebang (#!/usr/bin/perl), and is trying to execute the script in its own language rather than invoking Perl to run it.

Try using /bin/bash, and then your shebang line will work. Or, simply invoke perl explicitly: perl tt.pl.

Answer 3

I had similar error messages and found the reason to be that the perl file was using the wrong character encoding (don't ask me why this mattered to perl). Perl was installed correctly, paths were in order, script syntax was perfect (I even got the "use: command not found" error for a one line "Hello World!" script). Check that tt.pl is UTF8 no-BOM.

Answer 4

Thank you Gavin! You just saved me hours of troubleshooting. I had the same error as above and it turned out to be a characterset issue.