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#### 6.1.31 `sort`

Usage:

       sort [-down] [-nullsfirst] [-[no]parallel] <key-list>

Sorts the table according to the value of one or more algebraic expressions. The sort key expressions appear, as separate (space-separated) words, in `<key-list>`; sorting is done on the first expression first, but if that results in a tie then the second one is used, and so on.

Each expression must evaluate to a type that it makes sense to sort, for instance numeric. If the `-down` flag is used, the sort order is descending rather than ascending.

Blank entries are by default considered to come at the end of the collation sequence, but if the `-nullsfirst` flag is given then they are considered to come at the start instead.

By default, sorting is done sequentially for small tables and in parallel for large tables, but this can be controlled with the `-parallel` or `-noparallel` flag.

Syntax for the `<key-list>` argument is described in Section 10.

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STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page: http://www.starlink.ac.uk/stilts/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@jiscmail.ac.uk