bash - Cut hex addresses without having them expanded into text

Question

I'm getting a window id with this command and storing it into a variable

id=$(xdo id -n "piper" || xdo id -N "Piper")
echo $id
0x04000007 0x04000001

However, when I try to use cut or head to get only the first address, they convert the hex value to text. For example:

id=$(id | cut -f1 -d' ')
echo $id
uid=1007(user)

I've looked into both cut and head but haven't found any way to make them not (expand?) the hex value. I'd like to get the first value as it is.

question from:https://stackoverflow.com/questions/65910689/cut-hex-addresses-without-having-them-expanded-into-text

Answer 1

id (a command) is not the same as ${id} (a variable reference); and id does not return the same thing as xdo ... || xdo ...

Assuming the variable id has your hex codes, and said codes are separated by a space, you can use parameter expansion to pull the first hex code, eg:

$ echo ${id%% *}
0x04000007

## or

$ echo ${id// */}
0x04000007

## or

$ echo ${id// *}
0x04000007