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These commands work with (or produce) sorted files.
sort: Sort text files
sort sorts, merges, or compares all the lines from the given
files, or standard input if none are given or for a file of
`-'. By default,
sort writes the results to standard
sort [option]... [file]...
sort has three modes of operation: sort (the default), merge,
and check for sortedness. The following options change the operation
A pair of lines is compared as follows: if any key fields have been
sort compares each pair of fields, in the order
specified on the command line, according to the associated ordering
options, until a difference is found or no fields are left.
If any of the global options `Mbdfinr' are given but no key fields
sort compares the entire lines according to the
Finally, as a last resort when all keys compare equal (or if no
ordering options were specified at all),
sort compares the lines
byte by byte in machine collating sequence. The last resort comparison
honors the `-r' global option. The `-s' (stable) option
disables this last-resort comparison so that lines in which all fields
compare equal are left in their original relative order. If no fields
or global options are specified, `-s' has no effect.
sort (as specified for all GNU utilities) has no limits on
input line length or restrictions on bytes allowed within lines. In
addition, if the final byte of an input file is not a newline, GNU
sort silently supplies one.
If the environment variable
TMPDIR is set,
sort uses its
value as the directory for temporary files instead of `/tmp'. The
`-T tempdir' option in turn overrides the environment
The following options affect the ordering of output lines. They may be specified globally or as part of a specific key field. If no key fields are specified, global options apply to comparison of entire lines; otherwise the global options are inherited by key fields that do not specify any special options of their own.
Other options are:
sortcopies it to a temporary file before sorting and writing the output to output-file.
sortbreaks it into fields ` foo' and ` bar'. The field separator is not considered to be part of either the field preceding or the field following.
A position has the form `f.c', where f is the number of the field to use and c is the number of the first character from the beginning of the field (for `+pos') or from the end of the previous field (for `-pos'). The `.c' part of a position may be omitted in which case it is taken to be the first character in the field. If the `-b' option has been given, the `.c' part of a field specification is counted from the first nonblank character of the field (for `+pos') or from the first nonblank character following the previous field (for `-pos').
A `+pos' or `-pos' argument may also have any of the option letters `Mbdfinr' appended to it, in which case the global ordering options are not used for that particular field. The `-b' option may be independently attached to either or both of the `+pos' and `-pos' parts of a field specification, and if it is inherited from the global options it will be attached to both. If a `-n' or `-M' option is used, thus implying a `-b' option, the `-b' option is taken to apply to both the `+pos' and the `-pos' parts of a key specification. Keys may span multiple fields.
In addition, when GNU
sort is invoked with exactly one argument,
options `--help' and `--version' are recognized. See section Common options.
Historical (BSD and System V) implementations of
differed in their interpretation of some options, particularly
`-b', `-f', and `-n'. GNU sort follows the POSIX
behavior, which is usually (but not always!) like the System V behavior.
According to POSIX, `-n' no longer implies `-b'. For
consistency, `-M' has been changed in the same way. This may
affect the meaning of character positions in field specifications in
obscure cases. The only fix is to add an explicit `-b'.
uniq: Uniqify files
uniq writes the unique lines in the given `input', or
standard input if nothing is given or for an input name of
uniq [option]... [input [output]]
uniq prints the unique lines in a sorted file, i.e.,
discards all but one of identical successive lines. Optionally, it can
instead show only lines that appear exactly once, or lines that appear
more than once.
The input must be sorted. If your input is not sorted, perhaps you want
If no output file is specified,
uniq writes to standard
The program accepts the following options. Also see section Common options.
comm: Compare two sorted files line by line
comm writes to standard output lines that are common, and lines
that are unique, to two input files; a filename of `-' means
standard input. Synopsis:
comm [option]... file1 file2
The input files must be sorted before
comm can be used.
With no options,
comm produces three column output. Column one
contains lines unique to file1, column two contains lines unique
to file2, and column three contains lines common to both files.
@opindex -1 @opindex -2 @opindex -3 The options `-1', `-2', and `-3' suppress printing of the corresponding columns. Also see section Common options.
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