./*glob* or -- *glob* so names with dashes
won't become options.rm *rm ./*or
rm -- *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 do 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".
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.