Bug 845925

Summary:	test -n always returns 0 if evaluating variable
Product:	[Fedora] Fedora	Reporter:	Martin Kyral <mkyral>
Component:	coreutils	Assignee:	Ondrej Vasik <ovasik>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	17	CC:	kdudka, maxamillion, ovasik, p, twaugh
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Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	845927 845929 (view as bug list)		Environment:
Last Closed:	2012-08-06 07:27:52 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:
Bug Depends On:
Bug Blocks:	845927, 845929

Description Martin Kyral 2012-08-06 07:12:52 UTC

Description of problem:
According to the man page, "test -n STRING" returns true (0) if the STRING's length is non-zero and that it equivalent to "test STRING" (and contrary to "test -z STRING").

Version-Release number of selected component (if applicable):
coreutils-8.15-7.fc17.x86_64

How reproducible:
Always


Steps to Reproduce:
1. VAR=''
2. test -n $VAR ; echo $?
3. test $VAR ; echo $?

  
Actual results:
In step 2, the output is 0 (true in shell semantics).


Expected results:
In step 2, the output is 0 (false in shell semantics).

Additional info:
"test -n $VAR" returns 0 on both empty and non-empty string $VAR value. "test $VAR" and "test -z $VAR" give the expected values, ie. 0,1 on non-empty and 1,0 on empty $VAR values. Also, "test -n" gives correct output if a direct value is given.

Comment 1 Martin Kyral 2012-08-06 07:22:11 UTC

Expected results:
In step 2, the output is 1 (false in shell semantics).

Sorry for the typo..

Comment 2 Kamil Dudka 2012-08-06 07:27:52 UTC

(In reply to comment #0)
> 2. test -n $VAR ; echo $?

You need to write:

test -n "$VAR"

... so that "test" actually gets an empty string.  Otherwise shell will throw the empty string away.

Additionally, you are probably using the shell built-in command "test", not the executable /usr/bin/test from coreutils:

http://www.gnu.org/software/coreutils/faq/coreutils-faq.html#I-am-having-a-problem-with-kill-nice-pwd-sleep-or-test_002e