By default, any of the given pathnames which match an ignore pattern
will be output, one per line. If no pattern matches a given path,
nothing will be output for that path; this means that path will not be
ignored.
If --verbose is specified, the output is a series of lines of the form:
<source> <COLON> <linenum> <COLON> <pattern> <HT> <pathname>
<pathname> is the path of a file being queried, <pattern> is the
matching pattern, <source> is the pattern’s source file, and <linenum>
is the line number of the pattern within that source. If the pattern
contained a "!" prefix or "/" suffix, it will be preserved in the
output. <source> will be an absolute path when referring to the file
configured by core.excludesFile, or relative to the repository root
when referring to .git/info/exclude or a per-directory exclude file.
If -z is specified, the pathnames in the output are delimited by the
null character; if --verbose is also specified then null characters
are also used instead of colons and hard tabs:
<source> <NULL> <linenum> <NULL> <pattern> <NULL> <pathname> <NULL>
If -n or --non-matching are specified, non-matching pathnames will
also be output, in which case all fields in each output record except
for <pathname> will be empty. This can be useful when running
non-interactively, so that files can be incrementally streamed to
STDIN of a long-running check-ignore process, and for each of these
files, STDOUT will indicate whether that file matched a pattern or
not. (Without this option, it would be impossible to tell whether the
absence of output for a given file meant that it didn’t match any
pattern, or that the output hadn’t been generated yet.)
Buffering happens as documented under the GIT_FLUSH option in
git(1). The caller is responsible for avoiding deadlocks
caused by overfilling an input buffer or reading from an empty output
buffer.