SORT(1) BSD Reference Manual SORT(1)
sort - sort or merge text files
sort [-cmubdfinrH] [-t char] [-R char] [-k field1[,field2]] ... [-T dir] [-o output] [file] ...
The sort utility sorts text files by lines. Comparisons are based on one or more sort keys extracted from each line of input, and are performed lexicographically. By default, if keys are not given, sort regards each input line as a single field. The options are as follows: -c Check that the single input file is sorted. If the file is not sorted, sort produces the appropriate error messages and exits with code 1; otherwise, sort returns 0. sort -c produces no out- put, except the error messages on stderr. -m Merge only; the input files are assumed to be pre-sorted. -o output The argument given is the name of an output file to be used in- stead of the standard output. This file can be the same as one of the input files. -T dir Use dir as the directory for temporary files. The default is the contents of the environment variable TMPDIR or /var/tmp if TMPDIR does not exist. -u Unique: suppress all but one in each set of lines having equal keys. If used with the -c option, check that there are no lines with duplicate keys. The following options override the default ordering rules. When ordering options appear independent of key field specifications, the requested field ordering rules are applied globally to all sort keys. When attached to a specific key (see -k), the ordering options override all global ord- ering options for that key. -d Only blank space and alphanumeric characters are used in making comparisons. -f Considers all lowercase characters that have uppercase equivalents to be the same for purposes of comparison. -i Ignore all non-printable characters. -n An initial numeric string, consisting of optional blank space, optional minus sign, and zero or more digits (including decimal point) is sorted by arithmetic value. (The -n option no longer implies the -b option.) -r Reverse the sense of comparisons. -H Use a merge sort instead of a radix sort. This option should be used for files larger than 60Mb. The treatment of field separators can be altered using these options: -b Ignores leading blank space when determining the start and end of a restricted sort key. A -b option specified before the first -k option applies globally to all -k options. Otherwise, the -b op- tion can be attached independently to each field argument of the -k option (see below). Note that the -b option has no effect un- less key fields are specified. -t char char is used as the field separator character. The initial char is not considered to be part of a field when determining key offsets. Each occurrence of char is significant (for example, "charchar" delimits an empty field). If -t is not specified, the default field separator is a sequence of blank-space characters, and consecutive blank spaces do not delimit an empty field; further, the initial blank space is considered part of a field when determining key offsets. -R char char is used as the record separator character. This should be used with discretion; -R <alphanumeric> usually produces undesir- able results. The default record separator is newline. -k field1[,field2] Designates the starting position, field1, and optional ending po- sition, field2, of a key field. The -k option replaces the ob- solescent options +pos1 and -pos2. The following operands are available: file The pathname of a file to be sorted, merged, or checked. If no file operands are specified, or if a file operand is -, the stan- dard input is used. A field is defined as a maximal sequence of characters other than the field separator and record separator (newline by default). Initial blank spaces are included in the field unless -b has been specified; the first blank space of a sequence of blank spaces acts as the field separator and is included in the field (unless -t is specified). For example, by de- fault all blank spaces at the beginning of a line are considered to be part of the first field. Fields are specified by the -k field1[,field2] argument. A missing field2 argument defaults to the end of a line. The arguments field1 and field2 have the form m.n (m,n > 0) and can be followed by one or more of the letters b, d, f, i, n, and r, which correspond to the options discussed above. A field1 position specified by m.n is interpreted as the nth character from the beginning of the mth field. A missing .n in field1 means '.1', indicating the first character of the mth field; if the -b option is in effect, n is counted from the first non-blank character in the mth field; m.1b refers to the first non-blank character in the mth field. 1.n refers to the nth character from the beginning of the line; if n is greater than the length of the line, the field is taken to be empty. A field2 position specified by m.n is interpreted as the nth character (including separators) of the mth field. A missing .n indicates the last character of the mth field; m = 0 designates the end of a line. Thus the option -k v.x,w.y is synonymous with the obsolescent option +v-1.x-1 -w-1.y; when y is omitted, -k v.x,w is synonymous with +v-1.x-1 -w.0. The obsolescent +pos1 -pos2 option is still supported, except for -w.0b, which has no -k equivalent. The sort utility shall exit with one of the following values: 0 Normal behavior. 1 On disorder (or non-uniqueness) with the -c option. 2 An error occurred.
TMPDIR Path in which to store temporary files. Note that TMPDIR may be overridden by the -T option.
/var/tmp/sort.* default temporary directories output#PID temporary name for output if output al- ready exists
comm(1), join(1), uniq(1), radixsort(3)
A sort command appeared in Version 3 AT&T UNIX.
sort has no limits on input line length (other than imposed by available memory) or any restrictions on bytes allowed within lines. To protect data sort -o calls link(2) and unlink(2), and thus fails on protected directories. The current sort command uses lexicographic radix sorting, which requires that sort keys be kept in memory (as opposed to previous versions which used quick and merge sorts and did not). Thus performance depends highly on efficient choice of sort keys, and the -b option and the field2 argu- ment of the -k option should be used whenever possible. Similarly, sort -k1f is equivalent to sort -f and may take twice as long.
To sort files larger than 60Mb, use sort -H; files larger than 704Mb must be sorted in smaller pieces, then merged. MirOS BSD #10-current November 22, 2009 2
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