shell scripting while if string length != 0

[Dave [Hawk-Systems]]

for reasons best left unsaid, we need to pull in a file full of partial
commands, and run them via a shell script on occasion, removing each command as
we run it.  Have managed to hack togetherthe following shell script, but and
stumped on something simple because of my lack of shell knowledge;

the file that holds out commands
  <file_o_commands>
	Server1 df -k
	Server2 df -k
	Server3 top | grep myprog
	Server4 who

add new commands to the end of the file with
  echo "Server2 who" >> /path/to/file_o_commands

then when we need to, run through the commands
  <file_to_run_stuff>
	#!/bin/sh
	# get top command
	DOCOMMAND=`head -n 1 /path/to/file_o_commands`
	# remove that command
	cat /path/to/file_o_commands | sed '1d' > /path/to/file_o_commands
	# run that command
	ssh ${DOCOMMAND}

this works as intended with 1 exception, we need to add a while in there to loop
through the file and stop processing an exit when `head -n 1
/path/to/file_o_commands` does not return a line.

I almost want to borrow -n from if

while [ -n (DOCOMMAND=`head -n 1 /path/to/file_o_commands`) ] do
 ...rest of script...
done

Anyone care to enlighten me a bit?

Dave