Occassionally, I have had users complain about strange characters when they use xterm or cmdtool. But most of the time, it has to do with their TERM variable. Here's what you can do to check for it.
#echo $TERM (see what value is in the variable)
If its output is not what you expected, set the correct value.
For Sun:
#sh
#TERM=sun
#export TERM
For most others:
#TERM=vt100
#export TERM
For C shell:
#csh
#setenv TERM sun
or
#setenv TERM vt100
Note: TERM must match one of the terminal types listed in the /usr/lib/terminfo directory.