perl -lne 'print (split(/:/))[0]' /etc/passwd should be typed as-is on the shell command line. The script version of it would be:

open(PASSWD, '/etc/passwd/')
or die("Can't open the system password file: $!\n");

print((split(/:/))[0], "\n")
   while (<PASSWD>);

close(PASSWD);
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perl -lne 'print ((split /:/)[0])' /etc/passwd
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I noticed that you specified that the output should contain the user name as well as the name, but your code only displayed the user name. If you need both:

perl -lne 'print ((split /:/)[0] . " " . (split /:/)[4])' /etc/passwd
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You can also use this:

perl -wlne 'print join " ", (split /:/)[0, 4]' /etc/passwd
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And arbitrarily playing golf:

perl -lne 'print "@{[(split /:/)[0, 4]]}"' /etc/passwd
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Or particularly well suited to -a and -F:

perl -F: -lane 'print "@F[0, 4]"' /etc/passwd
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--
[ e d @ h a l l e y . c c ]

I think you mean:

#!/usr/bin/perl
#
                                                                      
+          
                                                                      
+          
while ( my $user = (getpwent())[0])
{
   print $user,"\n";
}
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/J\

# cli:
perl -pne 's/(.+?):.+/user_$. $1_$./' /etc/passwd

# or from file:

#!/usr/bin/perl -np
s/(.+?):.+/user_$. $1_$./
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You'll need a plus after print, like this: print+(split(/:/))[0]

(Update: see the beginning of perldoc perlfunc if you don't know why.)

You'll need the perl options and arguments in the shebang line, or make a shell script of this, like

#!/bin/sh
perl -lne 'print+(split(/:/))[0]' /etc/passwd
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#!/usr/bin/perl -ln
BEGIN{ @ARGV = "/etc/passwd"; }
print+(split(/:/))[0]
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#!/usr/bin/perl -w
@ARGV = "/etc/passwd";
$\ = $/;
while(<>) {
print+(split(/:/))[0];
}
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updateAmbrus read more carefully than I. new text and strikes are updates

Please keep followups (such as this is, mimimally) in the original thread rather than starting a new one, Reposting an essentially verbatim question to a new node is NOTNOT regarded as honorable conduct in the monastery, particularly when the monks have already replied to your original ( password file problem, posted 3 days earlier than this one); offering answers most of which you do NOT appear to have studied and explaining WHY some of what you've posted WON'T WORK.

Failing to use <code> tags around your sample of what "output needs to be..." and your error messages is conterproductive, as omitting them lessens the readability of your post.

Please consult: How do I post a question effectively? AND (if you need more on formatting) Writeup Formatting Tips. Note that <code> tags are allowed around content that is NOT code, when their use makes your post more legible.

... and you may want to review the use of "-lne" (ps: that's one that's already been answered in a reply to your original post), and start using warnings and strict, qv.

You are basically right, but note the first sentence of the repost is new, and is an answer to Re: password file problem.

perl -aF: -lpe'$_=$F[0]' /etc/passwd
perl -le'print while $_=getpwent'
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You mean aside from Unix::PasswdFile, Passwd::Solaris and Passwd::Linux, or AnyData::Format::Passwd?

Or the built-in getpwent and friends? (Which has the benefit of probably honoring the local system's NIS or other remote password source)

Nope. nothing.

Update: OK, those middle two are for adding and removing new entries from the corresponding OS' passwd files rather than parsing out contents so they probably don't count as "parsing passwd" modules.

There's a function -- getpwent, so I guess there hasn't been as much need for it. (besides, it's just a colon delim file, so most other parsing programs could do it).

I'd also like to point out that there is no 'name' field in a passwd file -- it's the gecos field, which contains a comma seperated list of optional comments, the first of which is typically the name. (which is why you get odd behavior when someone tries entering a name in 'last, first' format.) From perldoc -f getpwent :

The exact meaning of the $gcos field varies but it usually contains the real name of the user (as opposed to the login name) and other information pertaining to the user. Beware, however, that in many system users are able to change this information and therefore it cannot be trusted and therefore the $gcos is tainted (see perlsec). The $passwd and $shell, user's encrypted password and login shell, are also tainted, because of the same reason.

Maybe I have put the wrong name - it is quite "silent",
but what can be more expressive than usermod?

#!/usr/bin/perl

use strict;
use Linux::usermod;

my %users =  Linux::usermod::users();

print join "\n", keys %users

__END__

# STDOUT:
backup
bin
cv
daemon
games
gnats
helpdesk
identd
irc
list
lp
mail
man
mysql
netsaint
news
nobody
operator
popa3d
postfix
postgres
proxy
reni
root
snort
spong
sshd
su
sync
sys
uucp
vidul
vis
www-data

# all those looks like system user accounts to me :)
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