sqlcmd -v parameter ignored in PowerShell - powershell

Question

I've read the documentation (sqlcmd Utility), but I can't get sqlcmd's -v parameter to work as expected.
Assuming this SQL script (echo.sql):
:setvar THE_PATH C:\Users\Craig\Desktop
PRINT 'THE_PATH: $(THE_PATH)'
:setvar THE_TOP 10
PRINT 'THE_TOP: $(THE_TOP)'
When run at the PowerShell prompt without the -v argument set:
PS> sqlcmd -E -S 'server' -d 'database' -i '.\echo.sql'
THE_PATH: C:\Users\Craig\Desktop
THE_TOP: 10
Setting the numeric variable (THE_TOP) are ignored:
PS> sqlcmd -E -S 'server' -d 'database' -i '.\echo.sql' -v THE_TOP=5
PS> sqlcmd -E -S 'server' -d 'database' -i '.\echo.sql'
THE_PATH: C:\Users\Craig\Desktop
THE_TOP: 10
If I eliminate the default value for THE_TOP in echo.sql, it reinforced the assertion that the parameter is being ignored:
:setvar THE_TOP
PRINT 'THE_TOP: $(THE_TOP)'
PS> sqlcmd -E -S 'server' -d 'database' -i '.\echo.sql' -v THE_TOP=5
THE_PATH: C:\Users\Craig\Desktop
THE_TOP: $(THE_TOP)
If I attempt to set the THE_PATH parameter, I get:
PS> sqlcmd -E -S 'server' -d 'database' -i '.\echo.sql' -v THE_PATH="C:\path"
Sqlcmd: ':\path': Invalid argument. Enter '-?' for help.
What is the correct -v syntax?

Answer 1

OK, this is retarded.
If :setvar is used in the script:
:setvar THE_TOP
PRINT 'THE_TOP: $(THE_TOP)'
then you attempt to set it at the PowerShell prompt, you'll get an error:
PS> sqlcmd -E -S server -d database -i .\echo.sql -v THE_TOP=5
'THE_TOP' scripting variable not defined.
However, if you DO NOT set it in the script:
-- variable disabled
-- :setvar THE_PATH
PRINT 'THE_TOP: $(THE_TOP)'
then you attempt to set it at the PowerShell prompt, then it will work as (not really) expected:
PS> sqlcmd -E -S server -d database -i .\echo.sql -v THE_TOP=5
THE_TOP: 5
** edit **
To supply a dynamically-generated path as a parameter to a script file (extract.sql):
:out $(THE_PATH)\extract.csv
SELECT *
FROM the_table
WHERE the_key = $(THE_ID)
...
Execute in PowerShell session:
PS> $cd = Get-Location
PS> sqlcmd -E -S 'server' -d 'database' -i '.\extract.sql' -v THE_ID=5 THE_PATH=`"$cd\build`"