sort(1) sort(1) NAME sort - sort and/or merge files SYNOPSIS sort [-cmu] [-ooutput] [-ykmem] [-zrecsz] [-bdfiMnr] [-tx] [-kkeydef] [+pos1 [-pos2]] [-T tdir] [files] DESCRIPTION The sort command sorts lines of all the named files together and writes the result on the standard output. The standard input is read if - is used as a filename or no input files are named. Comparisons are based on one or more sort keys extracted from each line of input. By default, there is one sort key, the entire input line, and ordering is lexicographic by bytes in machine collating sequence. sort processes supplementary code set characters according to the locale specified in the LC_CTYPE and LC_COLLATE environment variables [see LANG on environ(5)], except as noted below. Supplementary code set characters are collated in code order. The following options alter the default behavior: -c Check that the input file is sorted according to the ordering rules; give no output unless the file is out of sort. -m Merge only, the input files are assumed to be already sorted. -u Unique: suppress all but one in each set of lines having equal keys. If used with -c, check that there are no lines with duplicate keys, in addition to checking that the input file is sorted. -ooutput The argument given is the name of an output file to use instead of the standard output. This file may be the same as one of the inputs. -ykmem The amount of main memory used by sort has a large impact on its performance. Sorting a small file in a large amount of memory is a waste. If this option is omitted, sort begins using a system default memory size (64Kb), and continues to use more space as needed, up to a maximum equal to one eighth of physical memory. If this option is presented with a value (kmem), sort will start using that number of kilobytes of memory, unless the administrative minimum or maximum is violated, in which case the corresponding extremum will be used. sort will continue to allocate memory until a limit is reached. This limit is capped at 2Gb and computed to be the larger of the value given to the -y option and one half of physical memory. Thus, -y0 is guaranteed to start with minimum memory. By convention, -y (with no argument) starts with maximum memory; on SGI systems, -y (with no argument) starts with half of the total physical memory on the system (and the limit on memory usage is set to one half of physical memory as well). -zrecsz The size of the longest line read is recorded in the sort phase so buffers can be allocated during the merge phase. If the sort phase is omitted via the -c or -m options, a popular system default size will be used. Lines longer than the buffer size will cause sort to terminate abnormally. Supplying the actual number of bytes in the longest line to be merged (or some larger value) will prevent abnormal termination. If the sort phase is not omitted, then the maximum line size is calculated and used as the recsz, overriding the value of -z. Thus, the -z option is significant only when used with -c or -m. -T tdir The argument given is used as a directory where any temporary files required will be created. The TMPDIR environment variable will override this option. Sort keys can be specified using the options: -kfield_start[type][,field_end[type]] Defines a key field that begins at field_start and ends at field_end inclusive(provided that field_end does not precede field_start). A missing field_end means the end of the line. A field comprises a maximal sequence of non-separating characters and, in the absence of option -t , any preceding field separator. The field_start portion of the argument has the form: field_number[.first_character] Fields and characters within fields are numbered starting with 1. The field_number and first_character pieces, interpreted as positive decimal integers, specify the first character to be used as part of a sort key. If first_character is omitted, it refers to the first character of the field. The field_end portion of the argument has the form: field_number[.last_character] The field_number is as described above for field_start. The last_character piece, interpreted as a non-negative decimal integer, specifies the last character to be used as part of the sort key. If last_character evaluates to zero or last_character is omitted, it refers to the last character of the field specified by field_number. type is a modifier from the list of characters bdfinr. Each modifier behaves like the corresponding options(see below), but apply only to the key field to which they are attached. +pos1, -pos2 This is an obsolescent form of -k. pos1 corresponds to field_start, pos2 corresponds to field_end, except that both fields and characters are numbered from zero instead of one. The optional type modifiers are the same as in -k option. The following options override the default ordering rules. -d ``Dictionary'' order: only letters, digits, and blanks (spaces and tabs) are significant in comparisons. No comparison is performed for multibyte characters. -f Fold lowercase letters into uppercase for the purpose of comparison. Does not apply to multibyte characters. -i Ignore non-printable characters. Multibyte and embedded NULL characters are also ignored. -M Compare as months. The first three non-blank characters of the field are folded to uppercase and compared. Month names are processed according to the locale specified in the LC_TIME environment variable [see LANG on environ(5)]. For example, in an English locale the sorting order would be ``JAN'' < ``FEB'' < . . . < ``DEC.'' Invalid fields compare low to ``JAN.'' The -M option implies the -b option (see below). -n An initial numeric string, consisting of optional blanks, an optional minus sign, and zero or more digits with an optional decimal point, is sorted by arithmetic value. An empty digit string is treated as zero. Leading zeros and signs on zeros do not affect ordering. The -n option implies the -b option (see below). -r Reverse the sense of comparisons. -b Ignore leading blanks when determining the starting and ending positions of a restricted sort key. -tx Use x as the field separator character; x is not considered to be part of a field (although it may be included in a sort key). Each occurrence of x is significant (for example, xx delimits an empty field). x may be a supplementary code set character. The default field separators are blank characters. When ordering options appear before restricted sort key specifications, the requested ordering rules are applied globally to all sort keys. When attached to a specific sort key (described below), the specified ordering options override all global ordering options for that key. When there are multiple sort keys, later keys are compared only after all earlier keys compare equal. Except when the -u option is specified, lines that otherwise compare equal are ordered as if none of the options -d, -f, -i, -n or -k were present (but with -r still in effect, if it was specified) and with all bytes in the lines significant to the comparison. EXAMPLES Sort the contents of infile with the second field as the sort key: sort -k2 infile Sort, in reverse order, the contents of infile1 and infile2, placing the output in outfile and using the first character of the second field as the sort key: sort -r -o outfile -k 2.1,2.1 infile1 infile2 Sort, in reverse order, the contents of infile1 and infile2 using the first non-blank character of the second field as the sort key: sort -r +1.0b -1.1b infile1 infile2 Print the password file [passwd(4)] sorted by the numeric user ID (the third colon-separated field): sort -t: +2n -3 /etc/passwd Sort the contents of the password file using the group ID (third field) as the primary sort key and the user ID (second field) as the secondary sort key: sort -t: +3 -4 +2 -3 /etc/passwd Print the lines of the already sorted file infile, suppressing all but the first occurrence of lines having the same third field (the options -um with just one input file make the choice of a unique representative from a set of equal lines predictable): sort -um +2 -3 infile FILES /var/tmp/stm??? /usr/lib/locale/locale/LC_MESSAGES/uxcore.abi language-specific message file [See LANG on environ (5).] SEE ALSO comm(1), join(1), uniq(1) NOTES Comments and exits with non-zero status for various trouble conditions (for example, when input lines are too long), and for disorder discovered under the -c option. When the last line of an input file is missing a newline character, sort appends one, prints a warning message, and continues. sort does not guarantee preservation of relative line ordering on equal keys. If the -i and -f options are both used, or if the -i and -d are both used, the last one given controls the sort behavior; it is not currently possible to sort with folded case or dictionary order and non-printing characters ignored, because of the method used to implement these options. Page 5