Re: exec, redirections and variable expansions

[Marc Herbert]

mike bakhterev a écrit :
> 
> Description:
>       Something is wrong with variable substitution in the exec invocation.
>       When i try to close file descriptor whose number is in variable X with
>       command:
> 
>               exec $X>&-

I think the operator is   2>   as a whole; you cannot split the two characters.
Operators are parsed before parameter expansion.

In other words, what you are trying to do is a bit like:

I=i F=f 
# Does not work either!
$I$F true; then echo foo; fi


You need eval:

  eval "$I$F true; then echo foo; fi" # Works
  eval "exec $X>&-"                   # Works