1.8 KiB
User selections
Synopsis
select <NAME>; do
<LIST>
done
select <NAME> in <WORDS>; do
<LIST>
done
# alternative, historical and undocumented syntax
select <NAME>
{
<LIST>
}
select <NAME> in <WORDS>
{
<LIST>
}
Description
This compound command provides a kind of menu. The user is prompted with
a numbered list of the given words, and is asked to input the index
number of the word. If a word was selected, the variable <NAME> is set
to this word, and the list <LIST> is
executed.
If no in <WORDS> is given, then the positional parameters are taken as
words (as if in "$@" was written).
Regardless of the functionality, the number the user entered is saved
in the variable REPLY.
Bash knows an alternative syntax for the select command, enclosing the
loop body in {...} instead of do ... done:
select x in 1 2 3
{
echo $x
}
This syntax is not documented and should not be used. I found the parser definitions for it in 1.x code, and in modern 4.x code. My guess is that it's there for compatiblity reasons. This syntax is not specified by POSIX(R).
Examples
# select <NAME> in <WORDS>; do
# <LIST>
# done
# meaning e.g.:
clear
echo
echo hit number key 1 2 or 3 then ENTER-key
echo ENTER alone is an empty choice and will loop endlessly until Ctrl-C or Ctrl-D
echo
select OPTIONX in beer whiskey wine liquor ; do
echo you ordered a $OPTIONX
break # break avoids endless loop -- second line to be executed always
done
# place some if else fi business here
# and explain how it makes sense that $OPTIONX is red but OPTIONX is black
# even though both are variables