JCols

Skip forward to the download section for instructions on downloading JCols if you`d rather not read this. This utility parses text files by applying a user specified expression to each line. The line may first be split into columns by whitespace (the Default) or by some regular expression (the -r option). The name "JCols" is simply an abbreviation of "Java Columns". This documentation can also be found in the README file included in the JAR file. This utility is an alternative to things like AWK. The utility only has a command line interface. If you`re interested in a application with a GUI to parse text files consider something like FlexText or File Parse, but I have not tried other of those programs. If you want a Java implementation of AWK look into jawk. Finally, in some cases the cut command or even BASh/sh`s set $line to Extract fields from a line may be sufficient. The distinguishing characteristics of JCols are that it is a small utility that allows arbitrary expressions in relatively familiar languages (Java and JavaScript) to be specified. Also, JCols` -r option, which allows arbitrary regular expression groups to be mapped to columns, does not seem to have an analogue in AWK. Part of the motivation behind this script was to find the fastest way that a user defined expression could be applied to each line in a file. Java was chosen as the host language due to it`s speed and portability. JavaScript was chosen as the embedded language due to it`s straight forward syntax and due to it being well supported in Java. In some cases this has proven to be 20 times as fast as the equivalent Python utility evaluating Python expressions on each line. This utility depends on Rhino for JavaScript support. Directly accessing Rhino instead of going through Java 1.6`s generic interface was determined to be much FASTER.