grep: Output Line Prefix Control
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1 2.1.4 Output Line Prefix Control
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1
1 When several prefix fields are to be output, the order is always file
1 name, line number, and byte offset, regardless of the order in which
1 these options were specified.
1
1 ‘-b’
1 ‘--byte-offset’
1 Print the 0-based byte offset within the input file before each
1 line of output. If ‘-o’ (‘--only-matching’) is specified, print
1 the offset of the matching part itself.
1
1 ‘-H’
1 ‘--with-filename’
1 Print the file name for each match. This is the default when there
1 is more than one file to search.
1
1 ‘-h’
1 ‘--no-filename’
1 Suppress the prefixing of file names on output. This is the
1 default when there is only one file (or only standard input) to
1 search.
1
1 ‘--label=LABEL’
1 Display input actually coming from standard input as input coming
1 from file LABEL. This is especially useful when implementing tools
1 like ‘zgrep’; e.g.:
1
1 gzip -cd foo.gz | grep --label=foo -H something
1
1 ‘-n’
1 ‘--line-number’
1 Prefix each line of output with the 1-based line number within its
1 input file. (‘-n’ is specified by POSIX.)
1
1 ‘-T’
1 ‘--initial-tab’
1 Make sure that the first character of actual line content lies on a
1 tab stop, so that the alignment of tabs looks normal. This is
1 useful with options that prefix their output to the actual content:
1 ‘-H’, ‘-n’, and ‘-b’. This may also prepend spaces to output line
1 numbers and byte offsets so that lines from a single file all start
1 at the same column.
1
1 ‘-Z’
1 ‘--null’
1 Output a zero byte (the ASCII NUL character) instead of the
1 character that normally follows a file name. For example, ‘grep
1 -lZ’ outputs a zero byte after each file name instead of the usual
1 newline. This option makes the output unambiguous, even in the
1 presence of file names containing unusual characters like newlines.
1 This option can be used with commands like ‘find -print0’, ‘perl
1 -0’, ‘sort -z’, and ‘xargs -0’ to process arbitrary file names,
1 even those that contain newline characters.
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