Advanced Bash−Scripting Guide

# May need to also press ENTER if a key not listed above pressed.
read −n3 key
# Read 3 characters.
echo −n "$key" | grep "$arrowup" #Check if character code detected.
if [ "$?" −eq $SUCCESS ]
then
echo "Up−arrow key pressed."
exit $SUCCESS
fi
echo −n "$key" | grep "$arrowdown"
if [ "$?" −eq $SUCCESS ]
then
echo "Down−arrow key pressed."
exit $SUCCESS
fi
echo −n "$key" | grep "$arrowrt"
if [ "$?" −eq $SUCCESS ]
then
echo "Right−arrow key pressed."
exit $SUCCESS
fi
echo −n "$key" | grep "$arrowleft"
if [ "$?" −eq $SUCCESS ]
then
echo "Left−arrow key pressed."
exit $SUCCESS
fi
echo −n "$key" | grep "$insert"
if [ "$?" −eq $SUCCESS ]
then
echo "\"Insert\" key pressed."
exit $SUCCESS
fi
echo −n "$key" | grep "$delete"
if [ "$?" −eq $SUCCESS ]
then
echo "\"Delete\" key pressed."
exit $SUCCESS
fi
Advanced Bash−Scripting Guide
echo " Some other key pressed."
exit $OTHER
# Exercises:
# −−−−−−−−−
# 1) Simplify this script by rewriting the multiple "if" tests
#+ as a 'case' construct.
# 2) Add detection of the "Home," "End," "PgUp," and "PgDn" keys.
The −t option to read permits timed input (see Example 9−4).
The read command may also "read" its variable value from a file redirected to stdin. If the file
contains more than one line, only the first line is assigned to the variable. If read has more than one
Chapter 11. Internal Commands and Builtins 129