Question

The following shell script takes a list of arguments, turns Unix paths into WINE/Windows paths and invokes the given executable under WINE.

#! /bin/sh  if [ '${1+set}' != 'set' ] then    echo 'Usage; winewrap EXEC [ARGS...]'   exit 1 fi  EXEC='$1' shift  ARGS=''  for p in '$@'; do   if [ -e '$p' ]   then     p=$(winepath -w $p)   fi   ARGS='$ARGS '$p'' done  CMD='wine '$EXEC' $ARGS' echo $CMD $CMD 

However, there’s something wrong with the quotation of command-line arguments.

$ winewrap '/home/chris/.wine/drive_c/Program Files/Microsoft Research/Z3-1.3.6/bin/z3.exe' -smt /tmp/smtlib3cee8b.smt Executing: wine '/home/chris/.wine/drive_c/Program Files/Microsoft Research/Z3-1.3.6/bin/z3.exe' '-smt' 'Z: mp\smtlib3cee8b.smt' wine: cannot find ''/home/chris/.wine/drive_c/Program' 

Note that:

1. The path to the executable is being chopped off at the first space, even though it is single-quoted.
2. The literal ‘\t’ in the last path is being transformed into a tab character.

Obviously, the quotations aren’t being parsed the way I intended by the shell. How can I avoid these errors?

EDIT: The ‘\t’ is being expanded through two levels of indirection: first, '$p' (and/or '$ARGS') is being expanded into Z:\tmp\smtlib3cee8b.smt; then, \t is being expanded into the tab character. This is (seemingly) equivalent to

Y='y\ty' Z='z${Y}z' echo $Z 

which yields

zy\tyz 

and not

zy  yz 

UPDATE: eval '$CMD' does the trick. The ‘\t‘ problem seems to be echo’s fault: ‘If the first operand is -n, or if any of the operands contain a backslash ( ‘\’ ) character, the results are implementation-defined.’ (POSIX specification of echo)

Answer 1

I you do want to have the assignment to CMD you should use

eval $CMD

instead of just $CMD in the last line of your script. This should solve your problem with spaces in the paths, I don’t know what to do about the ‘\t’ problem.