Date: Fri, 2 Feb 2007 13:48:31 +0100 From: J65nko <j65nko@gmail.com> To: Tigger <tigger@lvlworld.com> Cc: freebsd-questions@freebsd.org Subject: Re: unexpected result from sh script with `date` Message-ID: <19861fba0702020448u50ac68adqf205a3cd001e901f@mail.gmail.com> In-Reply-To: <20070202111156.GA41151@lilypie.com> References: <20070202111156.GA41151@lilypie.com>
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On 2/2/07, Tigger <tigger@lvlworld.com> wrote:
> Hello, the following simply sh script is outputting unexpected results.
> Any idea why?
>
> --script--
>
> #!/bin/sh
>
> started=`date`
>
> echo "Started at: $started"
> echo "Finished : "`date`
> exit
>
> --output--
>
> Started at: Fri Feb 2 22:13:51 EST 2007
> Finished : Fri Feb 2 22:13:51 EST 2007
>
> --problem--
>
> Between 'Feb' and '2', there is two spaces on the 'Started at' line,
> however the 'Finished' one only has 1 space.
>
> I know this sounds picky, but I was not expecting this at all.
>
> uname -a
> FreeBSD piglet 6.2-STABLE FreeBSD 6.2-STABLE #0: Fri Jan 19 04:13:20 EST
> 2007 tigger@piglet:/usr/obj/usr/src/sys/PIGLET i386
The same on OpenBSD here (ksh)
OpenBSD 4.0-current (GENERIC) #1194: Thu Nov 2 16:32:12 MST 2006
deraadt@i386.openbsd.org:/usr/src/sys/arch/i386/compile/GENERIC
It seems to depend whether the command substitution is within the
quote-delimited string, for 'echo' or outside that string, in other
words on its own.
------- script----------
#!/bin/sh
started=$(date)
echo "\$started within \" delimited string for echo"
echo "Started at: $started"
echo "Command substitution \$(date) within \" delimited string for echo"
echo "Finished : $(date)"
echo "Command substitution \$(date) outside \" delimited string for echo"
echo "Finished : "$(date)
echo "Command substitution \`date\` outside \" delimited string for echo"
echo "Finished : "$(date)
-----------------------------------
Output:
-------------------
$started within " delimited string for echo
Started at: Fri Feb 2 13:46:07 CET 2007
Command substitution $(date) within " delimited string for echo
Finished : Fri Feb 2 13:46:07 CET 2007
Command substitution $(date) outside " delimited string for echo
Finished : Fri Feb 2 13:46:07 CET 2007
Command substitution `date` outside " delimited string for echo
Finished : Fri Feb 2 13:46:07 CET 2007
---------------------------------------
Embedded inside the string there are two spaces between Feb and the 2,
as "stand-alone" there is only one space.
Strange indeed ;)
J65nko
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