zet: Take the union, intersection, etc of files
This is a command-line utility for doing set operations on files considered as
sets of lines. For instance, zet union x y z outputs the lines that occur in
any of x, y, or z, and zet intersect x y z those that occur in all of them.
Here are the subcommands of zet and what they do:
zet union x y zoutputs the lines that occur in any ofx,y, orz.zet intersect x y zoutputs the lines that occur in all ofx,y, andz.zet diff x y zoutputs the lines that occur inxbut not inyorz.zet single x y zoutputs the lines that occur in exactly one ofx,y, orz.zet multiple x y zoutputs the lines that occur in two or more ofx,y, andz.
Notes
- Each output line occurs only once, because we're treating the files as sets and the lines as their elements.
- We do take the file structure into account in one respect: the lines are
output in the same order as they are encountered. So
zet union xprints out the lines ofx, in order, with duplicates removed. - Zet translates UTF-16LE and UTF-16BE files to UTF-8, and ignores Byte Order Marks (BOMs) when comparing lines. It prepends a BOM to its output if and only if its first file argument begins with a BOM.
- Zet ignores all lines endings (
\r\nor\n) when comparing lines, so two input lines compare the same if their only difference is that one ends in\r\nand the other in\r. Zet ends each output line with\r\nif the first line of its first file argument ends in\r\n, and\notherwise (if the first line ends in\nor the first file has only one line and that line has no line terminator.) - Zet reads entire files into memory. Its memory usage is roughly proportional to the file size of its largest argument plus the size of the (eventual) output.
License
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.