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+# pipetools
+
+A collection of familiar and intuitive shell tools for processing text data in a pipeline. The only dependencies are POSIX utilities such as `tr` that should be available on any POSIX-compliant system.
+
+## Examples
+
+```sh
+echo foo bar baz | words
+# Output:
+foo
+bar
+baz
+```
+
+```sh
+echo foo bar baz | words | map '$IDX $ELEM' | filter '$IDX -gt 0'
+# Output:
+1 bar
+2 baz
+```
+
+```sh
+echo foo bar baz | words | map '$IDX $ELEM' | map '$IDX $(( $X0 + 10 )) $X1'
+# Output:
+0 10 foo
+1 11 bar
+2 12 baz
+```
+
+```sh
+echo foo bar baz | words | map '$(( $IDX + 1 ))' | reduce 1 '$(( $ACC * $ELEM ))'
+# Output:
+6
+```
+
+The tools all follow the same conventions:
+
+- Input is line-based (newline-separated). You can use `words` to convert whitespace to newlines.
+- `$IDX` is the index of the element in the input stream.
+- `$ELEM` is the element itself.
+- `$X0`, `$X1`, etc. are the whitespace separated words in the current element (think columns in a table).
+- `$ACC` is the accumulator for the reduce operation.
+
+The `$(( $X0 + $X1 ))` syntax is called arithmetic expansion, which allows for basic arithmetic operations within a shell script.
+
+## Installation
+
+Copy the contents of the `tools` directory to a directory in your PATH, or run the `install.sh` script to create symlinks automatically to your selected target directory.
+
+## Author
+
+Jan Tuomi <<jan@jantuomi.fi>>