Question

I’m trying to pass an asterisk symbol in quotes into my console app as a command line argument, and when I get it using System.Environment.getArgs, I actually get list of files in current directory. This is wrong, because I wrap asterisk into quotes, so text in quotes shouldn’t be substituted. How do I get command line arguments without such substitution in Windows under cygwin?

Answer 1

If you enclose it in single quotes, '*' it doesn’t get expanded, but the two inverted commas get through into the result of getArgs (see below), so you’d need to remove them later.

The reason "*" is expanded in windows is that inverted commas are legitimate as part of a globbable filename , because of spaces. You might want to del "temp file *.dat" at some point.

module ListArgs where
 import System.Environment
 main = getArgs >>= print

gives:

[1 of 1] Compiling ListArgs             ( ListArgs.hs, ListArgs.o )
Linking ListArgs.exe ...

D:\Files\Andrew\prog\haskell\utils>ListArgs.exe *
["HereDoc.hs","IOutils.lhs","SugaredApplicative.hs","ListArgs.exe","ListArgs.hi","ListArgs.hs","ListArgs.o"]

D:\Files\Andrew\prog\haskell\utils>ListArgs.exe "*"
["HereDoc.hs","IOutils.lhs","SugaredApplicative.hs","ListArgs.exe","ListArgs.hi","ListArgs.hs","ListArgs.o"]

D:\Files\Andrew\prog\haskell\utils>ListArgs.exe '*'
["'*'"]

D:\Files\Andrew\prog\haskell\utils>ListArgs.exe '*
["'*"]

D:\Files\Andrew\prog\haskell\utils>ListArgs.exe -*
["-*"]