Windows batch

IF and ELSE

The else needs to be on the same "line" as the if. From IF /? 'The ELSE clause must occur on the same line as the command after the IF.'

if "zz"=="TRUE" (
    copy /a zz + /a ee=/a zz
) else (
    copy /a e + /a %TMP%=/a e
)

Environment variables in batch files are expanded when a line is parsed.

In the case of blocks delimited by parentheses (as your if defined) the whole block counts as a "line" or command and it is read once. This means that all occurrences of %FOO% are replaced by their values before the block is run. Therefore %FOO% will be replaced by nothing as it was not set.

To solve this you can enable delayed expansion:

setlocal enabledelayedexpansion

Delayed expansion causes variables delimited by exclamation marks (!) to be evaluated on execution instead of parsing which will ensure the correct behavior in our case:

if not defined BAR (
    set FOO=1
    echo Foo: !FOO!
)

Text manipulation

• color 0a - changes text to green
• mode con: cols=80 lines=50 - changes cmd.exe window, no scroll available, type mode to display the current settings

References

• Using batch parameters
• Command-line reference A-Z For tylda parameters look for FOR
• What does %~d0 mean in a Windows batch file?