Use ./*glob*
or -- *glob*
so names with dashes won't become options.
Problematic code:
rm *
Correct code:
rm ./*
or
rm -- *
Rationale
Since files and arguments are strings passed the same way, programs can't properly determine which is which, and rely on dashes to determine what's what.
A file named -f
(touch -- -f
) will not be deleted by the problematic code. It will instead be interpreted as a command line option, and rm
will even report success.
Using ./*
will instead cause the glob to be expanded into ./-f
, which no program will treat as an option.
Similarly, --
by convention indicates the end of options, and nothing after it will be treated like flags (except for some programs possibly still special casing -
as e.g. stdin).
Note that changing *
to ./*
in GNU Tar parameters will add ./
prefix to path names in the created archive. This may cause subtle problems (eg. to search for a specific file in archive, the ./
prefix must be specified as well). So using -- *
is a safer fix for GNU Tar commands.
echo
and printf
does not have issues unless the glob is the first word in the command. ShellCheck 0.7.2+ does not warn for these commands.
For more information, see "Filenames and Pathnames in Shell: How to do it Correctly".