simple script to run a command, write log and loop...girl in need!

[WiccaChic]

Howdy all. Can someone give me a shell script skeleton I can use to do the following:

1. run command A
2. write to a log ONLY if command a errors
3. sleep for 3 seconds
4. loop back and do it again (and again, and again...)

I know, this is totally dumb I bet but I am not a unix genius.

 

[vgersh99]

while :
do
A
if [ $? -ne 0 ] ; then
echo "error running A" >> myLogFile.log
fi;
sleep 3;
done;

vlad
+----------------------------+
| #include<disclaimer.h> |
+----------------------------+

 

[chipperMDW]

#! /bin/sh
while true
do
    A || echo "Danger!" >>logfile
    sleep 3
done

 

[WiccaChic]

Thanks guys, both ways do the trick for me!