id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
104	ash/dash: Convert backslashes to forward slashes in PATH-like environment vars	dmik		"There is a fundamental problem in Unix-like shells when run under OS/2: backslashes in PATH-like environment variables. The backslashes will be interpreted as escape sequences by the shell in many cases which will produce incorrect results.

Examples of such cases include:

- Unquoted strings in shell scripts where backslashes will be simply dropped. E.g `sh -c '\abc\def.exe'` will try to start `abcdef.exe`).
- Special escape processing by the `echo` built-in. E.g. dash `echo` will treat backspaces as escape chars in ANSI escape sequences and will eat them/replace with special characters. Some other shells like mksh behave the same way which makes `echo` generally unsafe/unportable.

These cases are very common so a global solution is required — otherwise you have to patch each script to make path strings quoted and/or replace `echo` with an external `expr` command but this sounds like a really bad alternative.

The obvious solution is to fix all well-known PATH-like environment variables at the beginning of shell execution by replacing backslashes with slashes. The only drawback here is the in theory a PATH-like variable may be treated differently by a script but for variables like PATH/TMPDIR etc this is very unlikely (and even wrong) because they have a well-defined global system meaning so it looks safe to patch them. Another potential problem is custom script-specific variables that also contain paths but this is something we can't cover. A good idea is to introduce an environment variable recognized by shells that will contain the names of all PATH-like environment variables to fix (and that will default to PATH/TMPDIR etc)."	task	closed	major		dash		medium	fixed