[Cialug] [OT]: Shell script globbing

[Daniel A. Ramaley]

The script will be in sh. For testing i was using bash (my login shell) 
but since then i've confirmed that real sh behaves the same. The test 
machine is Solaris, where sh is really sh and not bash running in 
compatibility mode.

I did a bit of poking around on the machine. On Linux boxes, "[" is 
usually a symlink to "test", but i think bash (and bash when it is 
symlinked to sh) usually uses a built-in function instead. Solaris 
doesn't have "[", so the shell must be using a built-in to process the 
conditional rather than calling the external program.

How easy is it to switch to ksh? I've never used it, but it is fairly 
standard on *nix systems, isn't it?

On Thursday 20 December 2007 11:28, Major Stubble wrote:
>What shell are you using?
>
>ksh doesn't seem to have any issue with your first attempt:
>
>cthulu at rlyeh> touch file.bad
>cthulu at rlyeh> if [ -e *.bad ]; then echo bad; fi;
>bad
>cthulu at rlyeh> touch file2.bad
>cthulu at rlyeh> touch file3.bad
>cthulu at rlyeh> if [ -e *.bad ]; then echo bad; fi;
>bad
>cthulu at rlyeh> echo $SHELL
>/bin/ksh
>
>On Dec 20, 2007, at 11:21 AM, Daniel A. Ramaley wrote:
>> I have what should be a simple shell scripting problem. If any .bad
>> files exist, then the script should do some stuff (display an
>> error, do
>> some cleanup, and exit, though for testing i've simplified it). So
>> far i've come up with 2 solutions, one requiring a variable and
>> running "ls", the other requiring a seemingly superfluous "for"
>> loop. Is there a
>> more elegant solution i've not discovered?
>>
>> My first attempt, doesn't work because -e expects only 1 argument
>> and there may be multiple .bad files:
>>     if [ -e *.bad ] ; then
>>         echo Bad
>>     fi
>>
>> My first working solution, letting ls handle the glob and doing a
>> string
>> comparison on the result:
>>     GLOB=`ls *.bad 2> /dev/null`
>>     if [ -n "$GLOB" ] ; then
>>         echo Bad
>>     fi
>>
>> My second solution; the "if" is required because if no .bad files
>> exist
>> the loop will still run once with file set to the literal "*.bad":
>>     for file in *.bad ; do
>>         if [ -e $file ] ; then
>>             echo Bad
>>         fi
>>     done
>>
>> --------------------------------------------------------------------
>>-- --
>> Dan Ramaley                            Dial Center 118, Drake
>> University
>> Network Programmer/Analyst             2407 Carpenter Ave
>> +1 515 271-4540                        Des Moines IA 50311 USA
>> _______________________________________________
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>> Cialug at cialug.org
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>
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-- 
------------------------------------------------------------------------
Dan Ramaley                            Dial Center 118, Drake University
Network Programmer/Analyst             2407 Carpenter Ave
+1 515 271-4540                        Des Moines IA 50311 USA