grep: File and Directory Selection
2.1.6 File and Directory Selection
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‘-a’
‘--text’
Process a binary file as if it were text; this is equivalent to the
‘--binary-files=text’ option.
‘--binary-files=TYPE’
If a file’s data or metadata indicate that the file contains binary
data, assume that the file is of type TYPE. Non-text bytes
indicate binary data; these are either output bytes that are
improperly encoded for the current locale (⇒Environment
Variables), or null input bytes when the ‘-z’ (‘--null-data’)
option is not given (⇒Other Options).
By default, TYPE is ‘binary’, and ‘grep’ suppresses output after
null input binary data is discovered, and suppresses output lines
that contain improperly encoded data. When some output is
suppressed, ‘grep’ follows any output with a one-line message
saying that a binary file matches.
If TYPE is ‘without-match’, when ‘grep’ discovers null input binary
data it assumes that the rest of the file does not match; this is
equivalent to the ‘-I’ option.
If TYPE is ‘text’, ‘grep’ processes binary data as if it were text;
this is equivalent to the ‘-a’ option.
When TYPE is ‘binary’, ‘grep’ may treat non-text bytes as line
terminators even without the ‘-z’ (‘--null-data’) option. This
means choosing ‘binary’ versus ‘text’ can affect whether a pattern
matches a file. For example, when TYPE is ‘binary’ the pattern
‘q$’ might match ‘q’ immediately followed by a null byte, even
though this is not matched when TYPE is ‘text’. Conversely, when
TYPE is ‘binary’ the pattern ‘.’ (period) might not match a null
byte.
_Warning:_ The ‘-a’ (‘--binary-files=text’) option might output
binary garbage, which can have nasty side effects if the output is
a terminal and if the terminal driver interprets some of it as
commands. On the other hand, when reading files whose text
encodings are unknown, it can be helpful to use ‘-a’ or to set
‘LC_ALL='C'’ in the environment, in order to find more matches even
if the matches are unsafe for direct display.
‘-D ACTION’
‘--devices=ACTION’
If an input file is a device, FIFO, or socket, use ACTION to
process it. If ACTION is ‘read’, all devices are read just as if
they were ordinary files. If ACTION is ‘skip’, devices, FIFOs, and
sockets are silently skipped. By default, devices are read if they
are on the command line or if the ‘-R’ (‘--dereference-recursive’)
option is used, and are skipped if they are encountered recursively
and the ‘-r’ (‘--recursive’) option is used. This option has no
effect on a file that is read via standard input.
‘-d ACTION’
‘--directories=ACTION’
If an input file is a directory, use ACTION to process it. By
default, ACTION is ‘read’, which means that directories are read
just as if they were ordinary files (some operating systems and
file systems disallow this, and will cause ‘grep’ to print error
messages for every directory or silently skip them). If ACTION is
‘skip’, directories are silently skipped. If ACTION is ‘recurse’,
‘grep’ reads all files under each directory, recursively, following
command-line symbolic links and skipping other symlinks; this is
equivalent to the ‘-r’ option.
‘--exclude=GLOB’
Skip any command-line file with a name suffix that matches the
pattern GLOB, using wildcard matching; a name suffix is either the
whole name, or a trailing part that starts with a non-slash
character immediately after a slash (‘/’) in the name. When
searching recursively, skip any subfile whose base name matches
GLOB; the base name is the part after the last slash. A pattern
can use ‘*’, ‘?’, and ‘[’...‘]’ as wildcards, and ‘\’ to quote a
wildcard or backslash character literally.
‘--exclude-from=FILE’
Skip files whose name matches any of the patterns read from FILE
(using wildcard matching as described under ‘--exclude’).
‘--exclude-dir=GLOB’
Skip any command-line directory with a name suffix that matches the
pattern GLOB. When searching recursively, skip any subdirectory
whose base name matches GLOB. Ignore any redundant trailing
slashes in GLOB.
‘-I’
Process a binary file as if it did not contain matching data; this
is equivalent to the ‘--binary-files=without-match’ option.
‘--include=GLOB’
Search only files whose name matches GLOB, using wildcard matching
as described under ‘--exclude’. If contradictory ‘--include’ and
‘--exclude’ options are given, the last matching one wins. If no
‘--include’ or ‘--exclude’ options match, a file is included unless
the first such option is ‘--include’.
‘-r’
‘--recursive’
For each directory operand, read and process all files in that
directory, recursively. Follow symbolic links on the command line,
but skip symlinks that are encountered recursively. Note that if
no file operand is given, grep searches the working directory.
This is the same as the ‘--directories=recurse’ option.
‘-R’
‘--dereference-recursive’
For each directory operand, read and process all files in that
directory, recursively, following all symbolic links.
Info Catalog
grep: Context Line Control
grep: Command-line Options
grep: Other Options