Re: 'ls -n' opens password file for reading

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Article #1116

#1116

From: Ubben Greg
Date: Tue, 16 May 1989 03:00

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In article <1622@auspex.auspex.com> guy@auspex.auspex.com (Guy Harris) writes:
> he didn't say anything about "ls" without the "-n" flag or with other
> flags.  I presume he has a legitimate reason for wanting to do an "ls
> -n" on a system with either "/etc/passwd" or "/etc/group" missing.... 

Speaking of "ls -n" ... (INFORMATION ARTICLE)
For Bourne shell programmers, the following script magnifies the
speed difference between using "ls -n" and "ls -l" on System V:

	mkdir a && cd a		# Build playpen
	# Create a lot of files with different owners to make ls work hard
	sed 's/:.*//; s/.*/chown & & >&/' /etc/passwd | sh -
	timex ls -l		# Really slow (might want to >/dev/null)
	timex ls -n		# Much faster (though less portable)
	cd .. && rm -fr a	# Clean up (be careful)

You can instead just try LS on one of the more popular parents of home
directories for the same effect.  For this reason, I never use "ls -l"
in scripts when I don't need the actual owner or group names.

					-- Greg Ubben
					   bink@aplcen.apl.jhu.edu

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References: <1326@rivm05.UUCP> <128@softop.UUCP> <1622@auspex.auspex.com>

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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!rutgers!ukma!uflorida!indri!aplcen!bink
From: bink@aplcen.apl.jhu.edu (Ubben Greg)
Newsgroups: comp.bugs.sys5
Subject: Re: 'ls -n' opens password file for reading
Summary: Why you shouldn't use "ls -l" when "ls -n" will do.
Message-ID: <1245@aplcen.apl.jhu.edu>
Date: 16 May 89 03:00:43 GMT
References: <1326@rivm05.UUCP> <128@softop.UUCP> <1622@auspex.auspex.com>
Reply-To: bink@aplcen.apl.jhu.edu (Greg Ubben)
Distribution: na
Organization: The Johns Hopkins University, Baltimore MD
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