Re: Manual descriptions for -a file and -e file

[Andreas Kusalananda Kähäri]

On Mon, Mar 27, 2023 at 06:05:19AM +0000, uzibalqa wrote:
> 
> 
> In the bash manual under "6.4 Bash Conditional Expressions" I see the 
> following.
> 
> -a file
>     True if file exists.
> 
> -e file
>     True if file exists.
> 
> Could there be some brief comment about their difference?
> 
>   
> 
> 
> 

They are identical.  This is the C code that detects when -a and -e is
used:

  switch (op[1])
    {
    case 'a':                   /* file exists in the file system? */
    case 'e':
      return (sh_stat (arg, &stat_buf) == 0);

That's from here:
https://git.savannah.gnu.org/cgit/bash.git/tree/test.c#n526

These two lines of code have been unchanged since 1996 (bash 1.14).
There is no further clue in any commit messages, but I'm assuming this
is to align with the original ksh shell, which also has these two test
operators with the same semantics.  Whe the ksh shell used both -a and
-e, I don't know.

The original Bourse shell did not have -e nor -a for testing whether
a file exist.  You had to some other test that not only tested for
existence but also for e.g. readability, writability, file type or
something else.

-- 
Andreas (Kusalananda) Kähäri
SciLifeLab, NBIS, ICM
Uppsala University, Sweden

.