We needed to cleanup the iSeries, by removing all the unnecessary files. It seems to be always a good game to go haunting for large files. For me, going the IFS way was a discovery. The simple command below did all the job.
qsh cmd('find / -size +200000 -ls >/home/bigfiles.txt;')
Those familiar with Linux recognize here the find command. A subtle difference is in the number +200000, for the find command on QShell, you multiply this number by 512 to get the number of maximum bytes. Here, I'm looking for files having a size bigger than 200.000 * 512 ~ about 100MB. And it lists every file on IFS that has a size bigger than 100MB, but also every member of any physical file having a size greater than 100MB.
This takes an eternity to complete. PGM-FIND eats up to 20% UC, most of the time about 7% and for my case, this was not a real issue.