Variable comparison in powershell

Question

In my attempts to work powershell into some of my automation scripting I've encountered something I can't make sense of. Here's the scenario. I have two command prompt windows open on a Windows 8.1 machine. Both are pointed to the same directory. In one
window I launch the following powershell script:
do {
$request = get-content relayrequest.txt
echo $request
} until ($request -contains '1')
The text file initially contains 0, so the loop begins printing a column of 0's on the screen.  Meanwhile from the other command prompt window I type:
echo 1 >relayrequest.txt
and press enter.  The DO loop immediately reflects the change and begins printing a column of 1's on the screen, but does NOT end the loop.  Why isn't this variable comparison working.  I've tried it various ways and can't get the comparisons
to work.  What am I missing?

Answer 1

The result of Get-Content is an array if there is more than one line in the file.  But there isn't.
[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "
Doesn't matter:
PS C:\scripts> echo 1 > file.txt
PS C:\scripts> $x=Get-Content file.txt
PS C:\scripts> $x -contains '1'
True
¯\_(ツ)_/¯
It doesn't for this operation, but the idea that it's always going to be an array isn't quite right.
[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "
The script works as needed.  "-contains"  ssees the while line at once.  When it is not an array then it makes it an array of one and checks.
Food for thought:
PS C:\scripts> '11111' -contains '1'
False
PS C:\scripts> '1' -contains '1'
True
PS C:\scripts> ('11111')[0] -contains '1'
True
PS C:\scripts> ('11111').ToCharArray() -contains '1'
True
PS C:\scripts> ('22212').ToCharArray() -contains '1'
True
PS C:\scripts>
¯\_(ツ)_/¯