Shell scripts will also return to the source during execution, seeking to the next line in the file and rereading it.
You will often see errors in executing shell scripts if you edit them while they are running, because code has shifted around. For example: $ cat t.sh #!/bin/bash echo "bob"; sleep 1 echo "bob"; sleep 1 # etc, repeat the above several times While that is executing, edit the file in place, changing all of the occurrences of "bob" with 'tom" . Using nvi, it rewrites to the same inode, while sed creates a new one. So (at least for bash), when using vi, it picks up the changes mid-run, while sed, it continues using the old version. That actually surprised me. I *thought* that bash would reopen the file each time and pick up the new code in both cases. I learned something! If you do the same thing in a loop: while true; do echo "tom" sleep 1 done It does not seem to reread. But for a sourced file, it does not appear to reread the sourced file. I did not try all variations, like functions and what not. This is all likely documented, but spending less than 10 seconds in bash's info doc, I did not find it. But this is all probably by POSIX spec. Just not awake enough yet to figure out good search terms. I wouldn't be surprised if, in the early days, with limited disk space, self modifying Bourne shell scripts was a feature. I believe it was Ken Thompson who stated "The steady state of disks is 'full'." mrc
