Daniel Woods wrote:
>
> On Fri, 4 Aug 2000, Pierre Fortin wrote:
> > Daniel Woods wrote:
> > > > > This will work...
> > > > > cd {directory}
> > > > > ls -t | head -1
> > > > > or
> > > > > ls -t $HOME | head -1
> > > > >
> > > > > Using ksh (on Unix), this next line works to only accept files
> > > > > x=`ls -t | head -1`; if [[ -f $x ]]; then echo $x ;fi
> > > > > except that I could not get this to work with bash as
> > > > > x=`ls -t | head -1`; if [ -f $x ]; then echo $x ;fi
> > > > > since the '-f $x' seems to fail the test. Anyone know why ?
> > > >
> > > > As far as each shell goes those lines are direct equivalents. Is the directory
> > > > that you're working in changing? Only regular files will show up with either
> > > > command.
> > > >
> > > > Tony
> > >
> > > I tried this on Linux (bash)
> > > x=`ls -t | head -1`; if [ -f $x ]; then echo $x ; else echo "NO" ;fi
> > > and "NO" kept being printed. I tried just the first part to set x
> > > and then "echo $x" and got a file name 'xxx', so the 'if...' should work
> > > (but it does not). When I tried "if [ -f xxx ]; ..." then it worked.
> > > So for some reason in bash, the '-f $x' is not being interpreted properly.
> > > I even tried on the command line...
> > > # x=xxx
> > > # echo $x
> > > xxx
> > > # if [ -f $x ]
> > > > then echo $x
> > > > else echo NO
> > > > fi
> > >
> > > NO
> > > # echo $x
> > > xxx
> > > #
> > >
> > > So it still won't work but $x *is* correct.
> > > I gave up and wrote the Perl script instead :)
> >
> > Use braces:
> >
> > $ x=mysignature
> > $ if [ -f ${x} ]
> > > then echo ${x}
> > > else echo NO
> > > fi
> > mysignature
>
> Does work (surprised), but did you also try:
> $ x=mysignature
> $ if [ -f ${x} ]; then echo ${x} ; else echo "NO" ;fi
> NO
>
> which does *not* work. I had tried ${x} before your suggestion
> and saw it failed, so I'm surprised the multi-line one works.
> This also does not work...
> $ x=mysignature
> $ if [ -f ${x} ]; then { echo ${x} }; else { echo "NO" } ; fi
> NO
Try:
$ if [ -f ${x} ]; then echo ${x} ; else echo "NO" ; fi
mysignature
Forgot to ask: do you _have_ a file called "mysignature"...?
WFM,
Pierre
> This is definitely one of those scratch-your-head-it-should-work
> things which annoys us because it becomes a challenge to fix.
>
> Oh well, on to more important things for now :)
>
> Thanks... Dan.
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