• return the last edited file

ls -ct1 | head -1

broken into elements:

ls -c #sorts by ctime, newest first
ls -clt #shows ctime and sorts by ctime
ls -cl #show ctime, sorts by name

• run a command in xterm, keep xterm open even after the process finished or exited with an error

xterm -xrm '*hold: true' -e $1 &   # this is to keep xterm from closing
pid1=$!  # this is to save the pid, in case you want to close it
disown   # this is to prevent the finishing shell from closing the xterm

explained here: http://stackoverflow.com/questions/11668558/open-several-xterm-windows-from-script-without-closing