7.4 tsort: Topological sort

tsort performs a topological sort on the given file, or standard input if no input file is given or for a file of `-'. Synopsis:

tsort [option] [file]

tsort reads its input as pairs of strings, separated by blanks, indicating a partial ordering. The output is a total ordering that corresponds to the given partial ordering.

For example

tsort <<EOF a b c d e f b c d e EOF

will produce the output

a b c d e f

tsort will detect cycles in the input and writes the first cycle encountered to standard error.

Note that for a given partial ordering, generally there is no unique total ordering.

The only options are `--help' and `--version'. See section 2. Common options.