Get list of variables whose name matches a certain pattern

Question

In bash

echo ${!X*}

will print all the names of the variables whose name starts with \'X\'.
Is it possible to get the same with an ar

Answer 1

Easiest might be to do a

printenv |grep D.*=

The only difference is it also prints out the variable's values.

Answer 2

env | awk -F= '{if($1 ~ /X/) print $1}'

Answer 3

This should do it:

env | grep ".*X.*"

Edit: sorry, that looks for X in the value too. This version only looks for X in the var name

env | awk -F "=" '{print $1}' | grep ".*X.*"

As Paul points out in the comments, if you're looking for local variables too, env needs to be replaced with set:

set | awk -F "=" '{print $1}' | grep ".*X.*"

Answer 4

This will search for X only in variable names and output only matching variable names:

set | grep -oP '^\w*X\w*(?==)'

or for easier editing of searched pattern

set | grep -oP '^\w*(?==)' | grep X

or simply (maybe more easy to remember)

set | cut -d= -f1 | grep X

If you want to match X inside variable names, but output in name=value form, then:

set | grep -P '^\w*X\w*(?==)'

and if you want to match X inside variable names, but output only value, then:

set | grep -P '^\w*X\w*(?==)' | grep -oP '(?<==).*'

Answer 5

Use the builtin command compgen:

compgen -A variable | grep X