Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
#!/bin/bash
# timeout.sh
# Written by Stephane Chazelas,
# and modified by the document author.
INTERVAL=5
# timeout interval
timedout_read() {
timeout=$1
varname=$2
old_tty_settings=`stty −g`
stty −icanon min 0 time ${timeout}0
eval read $varname # or just read $varname
stty "$old_tty_settings"
# See man page for "stty".
}
echo; echo −n "What's your name? Quick! "
timedout_read $INTERVAL your_name
# This may not work on every terminal type.
# The maximum timeout depends on the terminal.
# (it is often 25.5 seconds).
echo
if [ ! −z "$your_name" ] # If name input before timeout...
then
echo "Your name is $your_name."
else
echo "Timed out."
fi
echo
# The behavior of this script differs somewhat from "timed−input.sh".
# At each keystroke, the counter resets.
exit 0
Perhaps the simplest method is using the −t option to read.
Example 9−4. Timed read
#!/bin/bash
# t−out.sh (per a suggestion by "syngin seven)
TIMELIMIT=4
# 4 seconds
read −t $TIMELIMIT variable