On Wed, Aug 26, 2009 at 12:45 PM, Linda Walsh<b...@tlinx.org> wrote: > I was scripting and fixing some permissions in Win, > and had a var 'c' set to (no quotes in the var): 'C\windows\system32' <snip>
> I first bumped into this using the printf -v var "%q" feature, where > I expected it to doublequote the back slashes. But instead, it looked > like I got the same value assigned to v as though I'd just done a 'c=v' > > # printf -v v "%q" $c > # echo $v |hexdump -C > 00000000 43 3a 5c 77 69 6e 64 6f 77 73 5c 73 79 73 74 65 > |C:\windows\syste| > 00000010 6d 33 32 0a 00000014 here is what I get: $ echo $v | hexdump -C 00000000 43 3a 5c 5c 57 69 6e 64 6f 77 73 5c 5c 53 79 73 |C:\\Windows\\Sys| 00000010 74 65 6d 33 32 0a |tem32.| 00000016 if you run your test prog after setting "set -x" (or run it with bash -x testprog) you will see the double \\. <snip> > Note that [[ and [ return different results when the vars are unquoted. The bash keyword [[ and [ are different in several ways (word splitting does not occur for instance) in your example the difference is that = inside [[ ]] does pattern matching. (note that in the case of bash [ is also a builtin) * If you quote the right hand side variable, then the expression is taken literally, the test becomes: [[ 'C:\Windows\System32' != 'C:\\Windows\\System32' ]] and it's false. * If you don't quote the right hand side variable, then the expression is taken as a pattern, the test becomes [[ 'C:\Windows\System32' != C:\\Windows\\System32 ]] in this glob the the \ is consider as escaping the other \ and the 2 variables are equal. That explaine the differences. Now I'm not too sure why var='"*'"; [[ \* = $var ]] is false while var='\*' [[ \* = $var ]] is true
