bash-hackers-wiki/original_source/syntax/ccmd/user_select.txt

====== User selections ======

===== Synopsis =====
<code>
select <NAME>; do
  <LIST>
done
</code>

<code>
select <NAME> in <WORDS>; do
  <LIST>
done
</code>

<code>
# alternative, historical and undocumented syntax

select <NAME>
{
  <LIST>
}

select <NAME> in <WORDS>
{
  <LIST>
}
</code>

===== 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 [[syntax:basicgrammar#lists | 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 ''{<nowiki>...</nowiki>}'' instead of ''do <nowiki>...</nowiki> done'':
<code>
select x in 1 2 3
{
  echo $x
}
</code>
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 =====
<code bash>
# 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
</code>
===== Portability considerations =====

===== See also =====