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I'm trying to use a bash script for a study assignment. As a bash noob, I tried to adapt an existing one to suit my purpose: Compile/Make a C-program with different compile arguments, execute it and redirect its output to a file.

The script is as follows:

#!/bin/bash
EXECUTABLE=./PartitionedHashJoin
OUTFILE=results.txt
for sizelog2 in $(seq 0 20)
do
        for buckets in $(seq 2 2048)
        do
                size=$((1<<$sizelog2))
                make clean
                make PartitionedHashJoin NUM_RELATION_R=$sizelog2 NUM_BUCKETS=$buckets
                echo -n $sizelog2 " " $buckets " " >> $OUTFILE
                $EXECUTABLE >> $OUTFILE
        done
done

However, bash throws an error:

...: line 6: 11927 Illegal instruction: 4 $EXECUTABLE >> $OUTFILE

If I remove the redirecting of the executable's output, then it works.

I do not get what I could have typed wrong in the redirection - it works just fine in another example with just one loop. Google didn't have a suggestion so far for what I'm doing wrong.

Can anyone spot it?

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What does "file ./PartitionedHashJoin" report? Is that file executable? Try "test -x $EXECUTABLE && $EXECUTABLE >> $OUTFILE". –  ott-- Oct 18 '11 at 22:23
    
It's very unlikely that bash itself threw this error. It's far more likely your PartitionedHashJoin executable is blowing up. –  Keith Thompson Oct 18 '11 at 22:31
    
Aah, you are correct. facepalm The error seems to lie in the executable indeed. Seems to be a weird one though - but at least it's not the bash. Thanks! –  Patrick Oct 19 '11 at 15:21

1 Answer 1

The $EXECUTE >> $REDIRECT statement is not on line 6 in the script. So the error is not in the script but rather in the executable.

...: line 6: 11927 Illegal instruction: 4 $EXECUTABLE >> $OUTFILE

This is also easy to see because or the error text. "Illegal instruction" means that the CPU can not execute some command. It is theoretically possible, but bash is stable software and these error do not occur in mature software.

The text you replaced with an ellipsis usually contains the executable which died or threw an error. I bet 50 rep it wasn't "bash".

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