How to Read a File and Sort It by Length in Java and Output to Another File

Standard UNIX utility

sort

The sort command
Original author(south)	Ken Thompson (AT&T Bell Laboratories)
Developer(s)	Various open-source and commercial developers
Initial release	November 3, 1971; 50 years ago  (1971-eleven-03)
Operating organization	Multics, Unix, Unix-like, V, Program ix, Inferno, MSX-DOS, IBM i
Platform	Cross-platform
Type	Command
License	coreutils: GPLv3+

In computing, sort is a standard control line program of Unix and Unix-like operating systems, that prints the lines of its input or chain of all files listed in its argument list in sorted order. Sorting is done based on one or more than sort keys extracted from each line of input. By default, the entire input is taken as sort key. Blank space is the default field separator. The command supports a number of control-line options that tin vary by implementation. For case the "-r" flag will reverse the sort guild.

History [edit]

A sort control that invokes a general sort facility was first implemented within Multics.^[1] Later, it appeared in Version ane Unix. This version was originally written by Ken Thompson at AT&T Bong Laboratories. By Version four Thompson had modified information technology to use pipes, merely sort retained an option to name the output file considering information technology was used to sort a file in place. In Version 5, Thompson invented "-" to represent standard input.^[2]

The version of sort bundled in GNU coreutils was written by Mike Haertel and Paul Eggert.^[three] This implementation employs the merge sort algorithm.

Like commands are available on many other operating systems, for example a sort command is role of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.^[4]

The sort command has also been ported to the IBM i operating arrangement.^[five]

Syntax [edit]

sort [OPTION]... [FILE]...        

With no FILE, or when FILE is -, the control reads from standard input.

Parameters [edit]

Name	Description	Unix	Program 9	Inferno	FreeBSD	Linux	MSX-DOS	IBM i
-b, --ignore-leading-blanks	Ignores leading blanks.	Yes	Yes	No	Yes	Aye	No	Aye
-c	Check that input file is sorted.	No	Yes	No	Yes	Aye	No	Yeah
-C	Like -c, simply does non written report the first bad line.	No	No	No	Yes	Yes	No	No
-d, --dictionary-guild	Considers simply blanks and alphanumeric characters.	Aye	Yes	No	Yes	Yeah	No	Yes
-f, --ignore-case	Fold lower case to upper case characters.	Yeah	Aye	No	Yes	Yeah	No	Yes
-thousand, --general-numeric-sort, --sort=general-numeric	Compares co-ordinate to general numerical value.	Aye	Yes	No	Yeah	Yes	No	No
-h, --homo-numeric-sort, --sort=human-numeric	Compare human readable numbers (e.g., 2K 1G).	Yep	No	No	Yes	Yep	No	No
-i, --ignore-nonprinting	Considers but printable characters.	Yes	Aye	No	Yeah	Yes	No	Yes
-k, --key= POS1 [, POS2 ]	Offset a key at POS1 (origin 1), cease it at POS2 (default finish of line)	No	No	No	Yes	Yes	No	No
-m	Merge only; input files are causeless to be presorted.	No	Yep	No	Yep	Yeah	No	Yeah
-Thou, --calendar month-sort, --sort=calendar month	Compares (unknown) < 'January' < ... < 'Dec'.	Yes	Yes	No	Aye	Yes	No	No
-n, --numeric-sort, --sort=numeric	Compares co-ordinate to string numerical value.	Yeah	Yes	Aye	Yes	Yes	No	Yes
-o OUTPUT	Uses OUTPUT file instead of standard output.	No	Yeah	No	Aye	Yes	No	Yeah
-r, --reverse	Reverses the issue of comparisons.	Yes	Yes	Aye	Yes	Yes	No	Yeah
-R, --random-sort, --sort=random	Shuffles, but groups identical keys. Encounter also: shuf	Yes	No	No	Yes	Yes	No	No
-due south	Stabilizes sort by disabling terminal-resort comparison.	No	No	No	Yep	Yes	No	No
-S size, --buffer-size= size	Use size for the maximum size of the retentiveness buffer.	No	No	No	Yes	No	No	No
-tx	'Tab character' separating fields is 10.	No	Yeah	No	No	Yes	No	Aye
-t char, --field-separator= char	Uses char instead of non-blank to bare transition.	No	No	No	Yes	Yes	No	No
-T dir, --temporary-directory= dir	Uses dir for temporaries.	No	Yep	No	Aye	Yes	No	No
-u, --unique	Unique processing to suppress all just ane in each set of lines having equal keys.	No	Aye	No	Yes	Yeah	No	Aye
-5, --version-sort	Natural sort of (version) numbers within text	No	No	No	Yes	Yes	No	No
-w	Similar -i, merely ignore only tabs and spaces.	No	Yep	No	No	No	No	No
-z, --zero-terminated	Stop lines with 0 byte, not newline	No	No	No	Yes	Yes	No	No
--help	Display help and exit	No	No	No	Yes	Yes	No	No
--version	Output version data and exit	No	No	No	Yes	Yeah	No	No
/R	Reverses the event of comparisons.	No	No	No	No	No	Yep	No
/S	Specify the number of digits to determine how many digits of each line should exist judged.	No	No	No	No	No	Yes	No
/A	Sort past ASCII lawmaking.	No	No	No	No	No	Yeah	No
/H	Include hidden files when using wild cards.	No	No	No	No	No	Yes	No

Examples [edit]

Sort a file in alphabetical society [edit]

                        $            cat phonebook            Smith, Brett     555-4321            Doe, John        555-1234            Doe, Jane        555-3214            Avery, Cory      555-4132            Fogarty, Suzie   555-2314          

                        $            sort phonebook            Avery, Cory      555-4132            Doe, Jane        555-3214            Doe, John        555-1234            Fogarty, Suzie   555-2314            Smith, Brett     555-4321          

Sort past number [edit]

The -n option makes the plan sort co-ordinate to numerical value. The du control produces output that starts with a number, the file size, and so its output can be piped to sort to produce a list of files sorted by (ascending) file size:

                        $            du /bin/*            |            sort -n            4       /bin/domainname            24      /bin/ls            102     /bin/sh            304     /bin/csh          

The find command with the ls pick prints file sizes in the 7th field, and then a list of the LaTeX files sorted by file size is produced by:

                        $            detect . -name            "*.tex"            -ls            |            sort -k 7n          

Columns or fields [edit]

Use the -k option to sort on a certain cavalcade. For instance, use "-1000 ii" to sort on the second column. In old versions of sort, the +1 option made the program sort on the second cavalcade of data (+2 for the third, etc.). This usage is deprecated.

                        $            true cat zipcode            Adam  12345            Bob   34567            Joe   56789            Sam   45678            Wendy 23456          

                        $            sort -m 2n zipcode            Adam  12345            Wendy 23456            Bob   34567            Sam   45678            Joe   56789          

Sort on multiple fields [edit]

The -grand m,n option lets y'all sort on a key that is potentially equanimous of multiple fields (beginning at column yard, end at cavalcade n):

                        $            cat quota            fred 2000            bob 1000            an 1000            chad m            don 1500            eric 500          

                        $            sort -k2,2n -k1,1 quota            eric 500            an m            bob 1000            chad 1000            don 1500            fred 2000          

Here the first sort is done using column two. -k2,2n specifies sorting on the fundamental starting and ending with column 2, and sorting numerically. If -k2 is used instead, the sort key would begin at column two and extend to the finish of the line, spanning all the fields in betwixt. -k1,ane dictates breaking ties using the value in column 1, sorting alphabetically past default. Note that bob, and chad accept the same quota and are sorted alphabetically in the final output.

Sorting a piping delimited file [edit]

                        $            sort -k2,2,-k1,1 -t'|'            zipcode            Adam|12345            Wendy|23456            Sam|45678            Joe|56789            Bob|34567          

Sorting a tab delimited file [edit]

Sorting a file with tab separated values requires a tab character to be specified as the cavalcade delimiter. This illustration uses the shell's dollar-quote notation^{[6] [7]} to specify the tab every bit a C escape sequence.

                        $            sort -k2,2 -t            $'\t'            phonebook            Doe, John	555-1234            Fogarty, Suzie	555-2314            Doe, Jane	555-3214            Avery, Cory	555-4132            Smith, Brett	555-4321          

Sort in reverse [edit]

The -r option just reverses the gild of the sort:

                        $            sort -rk 2n zipcode            Joe   56789            Sam   45678            Bob   34567            Wendy 23456            Adam  12345          

Sort in random [edit]

The GNU implementation has a -R --random-sort option based on hashing; this is non a full random shuffle because information technology volition sort identical lines together. A true random sort is provided past the Unix utility shuf.

Sort past version [edit]

The GNU implementation has a -5 --version-sort option which is a natural sort of (version) numbers within text. Two text strings that are to be compared are split into blocks of letters and blocks of digits. Blocks of messages are compared alpha-numerically, and blocks of digits are compared numerically (i.east., skipping leading zeros, more than digits means larger, otherwise the leftmost digits that differ determine the result). Blocks are compared left-to-right and the get-go non-equal block in that loop decides which text is larger. This happens to piece of work for IP addresses, Debian package version strings and similar tasks where numbers of variable length are embedded in strings.

Come across likewise [edit]

• Collation
• List of Unix commands
• uniq
• shuf

References [edit]

1. ^ "Multics Commands". world wide web.multicians.org.
2. ^ McIlroy, G. D. (1987). A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 (PDF) (Technical report). CSTR. Bong Labs. 139.
3. ^ "sort(1): sort lines of text files - Linux man page". linux.die.net.
4. ^ "MSX-DOS2 Tools User'southward Manual - MSX-DOS2 TOOLS ユーザーズマニュアル". April 1, 1993 – via Internet Annal.
5. ^ IBM. "IBM System i Version vii.2 Programming Qshell" (PDF) . Retrieved 2020-09-05 .
6. ^ "The GNU Bash Reference Manual, for Bash, Version four.ii: Section three.1.ii.iv ANSI-C Quoting". Free Software Foundation, Inc. 28 December 2010. Retrieved i February 2013. Words of the class $'string' are treated especially. The word expands to string, with backslash-escaped characters replaced as specified by the ANSI C standard.
7. ^ Fowler, Glenn S.; Korn, David 1000.; Vo, Kiem-Phong. "KornShell FAQ". Archived from the original on 2013-05-27. Retrieved 3 March 2015. The $'...' string literal syntax was added to ksh93 to solve the problem of entering special characters in scripts. Information technology uses ANSI-C rules to interpret the string between the '...'.

Farther reading [edit]

• Shotts (Jr), William E. (2012). The Linux Command Line: A Complete Introduction. No Starch Press. ISBN978-1593273897.
• McElhearn, Kirk (2006). The Mac OS X Command Line: Unix Nether the Hood. John Wiley & Sons. ISBN978-0470113851.

External links [edit]

• Original Sort manpage The original BSD Unix program'due south manpage
• sort(1)  – Linux User Manual – User Commands
• sort(ane)  – Plan nine Developer's Manual, Volume 1
• sort(1)  – Inferno General commands Transmission
• Further details virtually sort at Softpanorama

boughnercablecony.blogspot.com

Source: https://en.wikipedia.org/wiki/Sort_%28Unix%29

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