tsort(1)tsort(1)NAMEtsort - Sorts an unordered list of ordered pairs (topological sort)
SYNOPSIStsort [file]
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
tsort: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
None
OPERANDS
Pathname of a test file to be ordered.
If no file operand is specified, tsort reads standard input.
DESCRIPTION
The tsort command reads from file or standard input an unordered list
of ordered pairs, builds an ordered list, and writes it to standard
output.
[Tru64 UNIX] For creating a subroutine library, do not use tsort; use
the following command in its place:
% ar -ts file.a
The input file should contain pairs of nonempty strings separated by
spaces. Pairs of different items indicate a relative order. Pairs of
identical items indicate presence, but no relative order.
[Tru64 UNIX] You can use tsort to sort the output of the lorder com‐
mand.
[Tru64 UNIX] If file contains an odd number of fields, tsort writes
the error message:
tsort: Specify an even number of data fields.
NOTES
The LC_COLLATE environment variable does not affect the actions of
tsort.
EXIT STATUS
The following exit values are returned: Successful completion. An
error occurred.
EXAMPLES
To create a subroutine library, enter: lorder charin.o scanfld.o scan.o
scanln.o | tsort | xargs ar qv libsubs.a
(Enter the command entirely on one line, not on two lines as shown
above.)
This creates a subroutine library named libsubs.a that contains
charin.o, scanfld.o, scan.o, and scanln.o. The ordering of the object
modules in the library is important. The ld command requires each mod‐
ule to precede all the other modules that it calls or references. The
lorder and tsort commands together add the subroutines to the library
in the proper order.
Suppose that scan.o calls scanfld.o and scanln.o. scanfld.o also calls
charin.o. First, the lorder command creates a list of pairs that shows
these dependencies:
charin.o charin.o scanfld.o scanfld.o scan.o scan.o scanln.o scanln.o
scanfld.o charin.o scanln.o charin.o scan.o scanfld.o
Next, the | (vertical bar) sends this list to the tsort command, which
converts it into the ordering you need:
scan.o scanfld.o scanln.o charin.o
Note that each module precedes the module it calls. charin.o, which
does not call another module, is last.
The second | (vertical bar) then sends this list to xargs, which con‐
structs and runs the following ar command:
ar qv libsubs.a scan.o scanfld.o scanln.o charin.o
This ar command creates the properly ordered library.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of tsort: Pro‐
vides a default value for the internationalization variables that are
unset or null. If LANG is unset or null, the corresponding value from
the default locale is used. If any of the internationalization vari‐
ables contain an invalid setting, the utility behaves as if none of the
variables had been defined. If set to a non-empty string value, over‐
rides the values of all the other internationalization variables.
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to multi‐
byte characters in arguments). Determines the locale for the format
and contents of diagnostic messages written to standard error. Deter‐
mines the location of message catalogues for the processing of LC_MES‐
SAGES.
SEE ALSO
Commands: ar(1), lorder(1), xargs(1)
Standards: standards(5)tsort(1)
