A strange linux command execution problem from Process

Thread view:

Bhanu - 16 May 2007 13:11 GMT

Hi All,

I am using Process class to run scripts on a Fedora Core Linux
bash shell
All of my scripts are running except tho one in which i am using diff
command.

I am using simple diff command. My script is

-------------------------------------------------------------------------------------
#/bin/sh

if [ $# -eq 0 ];
then
echo "Usage: newFile oldFile outputFile"
exit
fi

FILE1=$1
FILE2=$2

OUTPUT_FILE=$3

echo "diff -c $FILE1 $FILE2 > $OUTPUT_FILE"
#diff -c $FILE1 $FILE2 > $OUTPUT_FILE

diff -c $FILE1 $FILE2 > $OUTPUT_FILE

------------------------------------------------------------------------------------------------

And I am also consuming the error and output streams so not blocking
the process.
the process returns with exit value > 0.

It would be a great help to me. If you help me solve this problem.

-Thanks,
Ratnesh.

Reply to this Message

Gordon Beaton - 16 May 2007 13:38 GMT

> I am using simple diff command. My script is
>
> #/bin/sh

Your script is wrong. The above line should read:

#!/bin/sh

/gordon

--

Reply to this Message

Nigel Wade - 16 May 2007 14:19 GMT

>> I am using simple diff command. My script is
>>
[quoted text clipped - 3 lines]
>
> #!/bin/sh

Not necessarily a problem. The original is actually a comment (whether it's
meant to be or not) so the script will be run with the default shell rather
than being forced to use /bin/sh.

As to the return value, the script/shell will return the exit status of the last
command, in this case diff. If the files differ then diff, and hence the
script, will not return 0.

Signature

Nigel Wade, System Administrator, Space Plasma Physics Group,
University of Leicester, Leicester, LE1 7RH, UK
E-mail : nmw@ion.le.ac.uk
Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

Reply to this Message

Bhanu - 16 May 2007 15:27 GMT

> >> I am using simple diff command. My script is
>
[quoted text clipped - 17 lines]
> E-mail : n...@ion.le.ac.uk
> Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

Sorry for error in posting the message that line reads #!/bin/sh in
the script
somehow i did mistake while posting the message

But I figured out the error

I tried the following on command prompt

diff build.xml conf/invoker_config.xml > test.log

echo $?

and the result was amazingly 1.

Reply to this Message

Bhanu - 16 May 2007 15:30 GMT

> >> I am using simple diff command. My script is
>
[quoted text clipped - 17 lines]
> E-mail : n...@ion.le.ac.uk
> Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

The problem is something else
I just tried the following on command prompt.

diff -c build.xml conf/invoker_config.xml > test.log
echo $?

and the result was amazingly 1.

Reply to this Message

Bhanu - 16 May 2007 15:53 GMT

> >> I am using simple diff command. My script is
>
[quoted text clipped - 17 lines]
> E-mail : n...@ion.le.ac.uk
> Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

Now I found the root problem
diff command exits with 0 status only when 2 files are equal
for unequal files it returns 1.

:) ..

Reply to this Message

Lew - 16 May 2007 22:22 GMT

>>>> I am using simple diff command. My script is
>>>> #/bin/sh
[quoted text clipped - 17 lines]
> diff command exits with 0 status only when 2 files are equal
> for unequal files it returns 1.

You found this by reading Nigel's post, which you keep quoting, yes? The one
where he explained exactly that?

Signature

Lew

Reply to this Message

A strange linux command execution problem from Process

Free Magazines