Comments on: Windows tricks for erlangers

By: Ionut G. Stan

Ionut G. Stan — Mon, 26 Jan 2009 09:27:10 +0000

I’m not an Erlanger yet, I plan though to learn it, but I can share the way I execute something in a certain directory. I’m using Total Commander which has a command line at the bottom. Simply enter cmd right there, press enter and then you may execute any program you wish. Well, it must be on the PATH though.

By: Ulf Wiger

Ulf Wiger — Thu, 01 Jan 2009 17:26:38 +0000

@Barry: well, that would explain it. (:
When calling cmd from the registry, the command and arguments are given separately, so I don’t think double quoting will interfere with the %1, but I’ll give it a try when I get back to my own machine.

By: Barry Kelly

Barry Kelly — Thu, 01 Jan 2009 17:09:30 +0000

Cmd’s quoting rules, like Windows’ quoting rules, are odd and seemingly ill-defined. The quotes can nest almost magically, though.

Consider an application called ‘test me.exe’ in the current directory which prints out the number of command-line arguments (aside from the executable name). The following runs are possible:

cmd /k “test me”

Runs “test me”, and prints 0.

cmd /k “”test me” foo bar”

Runs “test me”, and prints 2.

cmd /k “”test me” “foo bar”"

Runs “test me”, and prints 1.

This behaviour is the same whether or not cmd /k is invoked from the command line, or from e.g. a shortcut. For example, the last example above, as a command line, looks like the following on my system:

%windir%\system32\cmd.exe /k “”c:\cygwin\home\barrkel\test me.exe” “foo bar”"

The extra level of quoting makes it problematic for expanding argument lists like %*, though, so you’d need to build it up out of shift etc. when writing a batch file.

By: Robert Virding

Robert Virding — Sat, 27 Dec 2008 20:51:11 +0000

I use the following small batch file which I liberally sprinkle in the directories where I work. I can just click on these to start an erlang in the current directory. Setting ERL_LIBS means that erlang will find my own and imported libraries which are not part of the distribution.

@echo off

rem Use my git directories as libraries
set ERL_LIBS=C:/msys/1.0/home/GameStudio/erlang

start “Erlang” “C:\Program Files\erl5.6.5\bin\werl.exe”
exit

By: Ulf Wiger

Ulf Wiger — Sat, 27 Dec 2008 13:19:07 +0000

Thanks. Yes, I did try ‘cmd /K’, but apparently, cmd.exe doesn’t like spaces in the following command, even if it’s enclosed within double quotes. I had an alternative path without spaces, but apparently, it doesn’t like symlinks either…

By: Barry Kelly

Barry Kelly — Sat, 27 Dec 2008 13:06:01 +0000

For command-line shells, consider using the prefix ‘cmd /k’, followed by the rest of your erlc command. Cmd is the command shell; /k makes it run the following arguments as a command but *not* exit the shell.

Alternatively, write a batch file that looks like:

@echo off
\erlc %*
pause

And pass it all the arguments for erlc. It will pause with “Press any key to continue…” before dismissing the window.