`$-` means the options in your current shell.
- `h` = hashall
- `i` = interactive
- `m` = monitor
- `B` = braceexpand
- `C` = noclobber
- `H` = histexpand
`${-#*i}` means:
- `-` = Take the shell options
- `#` = remove the leading match from the parameter
- `*i` = the pattern to search for
So this takes the string "himBCH", finds the prefix "hi", and removes it.
It looks like the goal is to only do these operations if the script is
running non-interactively, such as in a cron job, since I assume the
letters are always in the same order.
Useful bash resources for this kind of thing:
-
https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
-
https://www.gnu.org/software/bash/manual/html_node/Pattern-Matching.html
- https://tldp.org/LDP/abs/html/options.html
Moshe
--
Moshe Katz
mmk...@umd.edu
(301) 867-3732
<http://stackexchange.com/users/440421>
On Tue, Nov 17, 2020 at 9:05 AM Judah Milgram <milg...@cgpp.com> wrote:
> I mean: for i in file1 file2...
> (not f)
>
>
> On 11/17/20 9:00 AM, Judah Milgram wrote:
> > I've combed the man page to the best of my ability and can't figure out
> > this snippet from a bash script:
> >
> > for f in file1 file2.... do
> > if [ "${-#*i}" = "$-" ]; then do stuff...
> > done
> >
> > What are those two expansions? They expand consistently to mBCH and
> > himBCH which rings a bell somewhere but my lockdown-addled brain just
> > can't place it.
> >
> > thanks...
> > Judah
> >
> >
>
>
> --
> Judah Milgram
> milg...@cgpp.com
> 301-257-7069
>
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