Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
echo "var1 = $var1"
echo
# A single 'read' statement can set multiple variables.
echo −n "Enter the values of variables 'var2' and 'var3' (separated by a space or tab): "
read var2 var3
echo "var2 = $var2 var3 = $var3"
# If you input only one value, the other variable(s) will remain unset (null).
exit 0
A read without an associated variable assigns its input to the dedicated variable $REPLY.
Example 11−3. What happens when read has no variable
#!/bin/bash
echo
# −−−−−−−−−−−−−−−−−−−−−−−−−− #
# First code block.
echo −n "Enter a value: "
read var
echo "\"var\" = "$var""
# Everything as expected here.
# −−−−−−−−−−−−−−−−−−−−−−−−−− #
echo
echo −n "Enter another value: "
read
# No variable supplied for 'read', therefore...
#+ Input to 'read' assigned to default variable, $REPLY.
var="$REPLY"
echo "\"var\" = "$var""
# This is equivalent to the first code block.
echo
exit 0
Normally, inputting a \ suppresses a newline during input to a read. The −r option causes an
inputted \ to be interpreted literally.
Example 11−4. Multi−line input to read
#!/bin/bash
echo
echo "Enter a string terminated by a \\, then press ."
echo "Then, enter a second string, and again press ."
read var1 # The "\" suppresses the newline, when reading "var1".
# first line \
# second line
Chapter 11. Internal Commands and Builtins 127