- topological sort
The tsort command produces on the standard output a totally ordered list of items consistent with a partial ordering of items mentioned in the input file.
The input consists of pairs of items (nonempty strings) separated by blanks. Pairs of different items indicate ordering. Pairs of identical items indicate presence, but not ordering.
The following operand is supported:
A path name of a text file to order. If no file operand is given, the standard input is used.
Example 1 An example of the tsort command
example% tsort <<EOF a b c c d e g g f g e f EOF
produces the output:
a b c d e f g
See environ(5) for descriptions of the following environment variables that affect the execution of tsort: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.
The following exit values are returned:
An error occurred.
See attributes(5) for descriptions of the following attributes:
Odd data: there are an odd number of fields in the input file.