Verena Alishahi wrote: > last week I've updated my workstation cluster client (amd 64 bit) from > SuSE 10.0 to openSUSE 10.3. My bash-version is 3.2.25(1)-release. > ... > Both the bash-scripts and the output file are stored on an > NFS-Filesystem (on the workstation cluster server), so every client can > access them.
I believe the use of NFS to be the root cause of your problem. The NFS synchronization here will be related to the NFS version in the kernel. Changing that has caused this to change behavior. I don't think this is related to changes in bash's version. Effectively echo is the same echo as before. > | less local.sh > #!/bin/bash > OUTPUT=$HOME/bashtest/output.txt > INPUT_HOSTS=$HOME/bashtest/hosts.inp > REMOTE_SKRIPT=$HOME/bashtest/remote.sh > echo "created from $HOME/bashtest/local.sh" > $OUTPUT > for HOST in `cat $INPUT_HOSTS` > do > ~ echo $HOST >> $OUTPUT > ~ ssh $HOST $REMOTE_SKRIPT > ~ echo "" >> $OUTPUT > done Why are there '~' chars in the above lines? But the real problem is that you are going to be toggling back and forth between different nfs client hosts writing to the same file. The writes will look like this in very close succession: local >> $OUTPUT client1 >> $OUTPUT local >> $OUTPUT client2 >> $OUTPUT local >> $OUTPUT client3 >> $OUTPUT local >> $OUTPUT client4 >> $OUTPUT local >> $OUTPUT I am confident this will stress the nfs client subsystem to failure. The problem is one of distributed nfs cache coherency in the buffer cache. It is not trivial to solve this problem. You might be able to get more expert discussion of the problem on the nfs mailing lists. You might be able to convince yourself of this through brute force by adding sleep statements to slow things down enough to give enough time to flush the cache between writes. I am not advocating it as a solution but only as a debugging data point. Google for "useless use of cat". In different contexts such as removing and recreating the file you would normally see "stale nfs file handle" errors. I don't think there is anything that bash can do to affect this since it is just doing normal output. The reason you tripped into this wasn't the bash version update but the system kernel upgrade which brought in a new nfs subsystem. You might be able to affect things favorably by changing the mount options. Bob
