On Fri, 2008-05-16 at 17:03 +0930, Ian Blackwell wrote:
> Craig White wrote:
> > That works fine one CentOS 5 (double quotes and backtics) but not on
> > CentOS 4.6
> >
> > Thanks...I guess it's good enough for now.
> >
> > Craig
> >
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> >
> >
> I can only imagine it is "working" in 4.6 because the result of "grep
> entry_chooser.js /var/log/httpd/access_log" is either empty or 1
> "word". The test syntax [ -z xxx ] would report the "too many
> arguments" error whenever the grep returned more than one word. You can
> test this at your command line by typing in:-
> [ -z one ]
> and
> [ -z one two three four five ]
>
> The first will return "false" but you'll just see another bash prompt,
> the second will report the "too many arguments" error. This is
> certainly the case for me using RHEL4.6, so I would imagine CentOS4.6
> should be the same. You can also see it explained by these commands and
> results:-
> [irb@zaphod ~]$ [ -z ]
> [irb@zaphod ~]$ echo $?
> 0
> [irb@zaphod ~]$ [ -z one ]
> [irb@zaphod ~]$ echo $?
> 1
> [irb@zaphod ~]$[ -z one two three four ]
> -bash: [: too many arguments
> [irb@zaphod ~]$ echo $?
> 2
> [irb@zaphod ~]$
>
> I hope this helps you understand why it is "working" on one machine but
> not another.
>
> Ian
>
> PS: I always prefer $(cmd) to backtics for readability. e.g.
>
> if [ -z "$(grep entry_chooser.js /var/log/httpd/access_log)" ]
>
> PPS: grep -q works for me on RHEL4.6 and CentOS5.1
----
makes a lot of sense - thanks
Craig
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