Re: Bash - various feature requests

[Matthew Woehlke]

Richard Neill wrote:
> 1)substr support for a negative length argument.
> For example,
>   stringZ=abcdef
>   echo ${stringZ:2:-1}  #prints cde
>
> i.e. ${string:x:y}
>   returns the string, from start position x for y characters.
>   but, if x is negative, start from the right hand side
>   and if y is negative, print up to the end, -y.
>
> This would work the same way as PHP, and be extremely useful for, say, 
> removing an extension from a filename.

Sounds good, but your example is bad... how do you know how long the 
"extension" is? :-) Consider 'foo.txt', 'bar.tar.gz', 'core.1234', etc. 
But this would be useful for other things, I would think.

> 4)A way to find a relative directory path. i.e. the solution to:
>
>    If I were to start in directory  /home/me/x/y/z
>    and I wanted to get to /home/me/x/a/b/c
>
>    then, what argument would I need to provide to 'cd' ?

Answer: /home/me/x/a/b/c. Well, the shell's built-in may do the 
"obvious" thing, but if you are expecting to feed paths to programs this 
way, symlinks will come and bite you. :-) There a quite a few places 
"in" my home directory where '../foo' and ( cd .. ; ./foo )' are not 
equivalent.

> 5)An enhancement to read/readline, such that one can specify the initial 
> value with which the buffer is filled.

Well, that, and a way to specify possible completions. :-)

--
Matthew
"But I want to cast Magic Missile!"