Java is notoriously verbose, especially when used in a serious Enterprise Project™.

...so naturally, I made linesieve, a Python text munging tool to split output into sections and match/sub/split with the full power of Python's re module.

Here's an example of using it on a file listing (delay added to make it look cool):

ls -1 /* | linesieve -s '.*:' show bin match ^d head -n2 output

You can find short examples in the reference, and an advanced example below.

Features #

linesieve allows you to:

• split text input into sections
• apply filters to specific sections
• search and highlight success/failure markers
• match/sub/split with the full power of Python's re module
• shorten paths, links and module names
• chain filters into pipelines
• colors!

Here's a list of filters available in 1.0:

• head – Output the first part of sections.
• tail – Output the last part of sections.
• span – Output matching line spans.
• match – Search for pattern (think grep).
• split – Output selected parts of lines (think cut).
• sub – Replace pattern (think sed s///g).
• sub-paths – Shorten paths of existing files.
• sub-cwd – Make working directory paths relative.
• sub-link – Replace symlink targets.

Installing #

Install it using pip:

$ pip install --upgrade linesieve

Links #

You can find:

• the documentation at Read the Docs
• the code on GitHub
• the latest release on PyPI

Example #

Here's a juicy Java example – this linesieve command:

linesieve \
span -v -X \
    --start '^ (\s+) at \s ( org\.junit\. | \S+ \. reflect\.\S+\.invoke )' \
    --end '^ (?! \s+ at \s )' \
    --repl '\1...' \
match -v '^\s+at \S+\.(rethrowAs|translateTo)IOException' \
sub-paths --include '{src,tst}/**/*.java' --modules-skip 1 \
sub -X '^( \s+ at \s+ (?! .+ \.\. | com\.example\. ) .*? ) \( .*' '\1' \
sub -X '^( \s+ at \s+ com\.example\. .*? ) \ ~\[ .*' '\1' \
sub -X '
    (?P<pre> \s+ at \s .*)
    (?P<cls> \w+ )
    (?P<mid> .* \( )
    (?P=cls) \.java
    (?P<suf> : .* )
    ' \
    '\g<pre>\g<cls>\g<mid>\g<suf>'

... shortens this 76 line traceback:

12:34:56.789 [main] ERROR com.example.someproject.somepackage.ThingDoer - exception while notifying done listener
java.lang.RuntimeException: listener failed
    at com.example.someproject.somepackage.ThingDoerTest$DummyListener.onThingDone(ThingDoerTest.java:420) ~[tests/:?]
    at com.example.someproject.somepackage.ThingDoer.doThing(ThingDoer.java:69) ~[library/:?]
    at com.example.otherproject.Framework.doAllTheThings(Framework.java:1066) ~[example-otherproject-2.0.jar:2.0]
    at com.example.someproject.somepackage.ThingDoerTest.listenerException(ThingDoerTest.java:666) ~[tests/:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
    ...
    ... 60+ more lines of JUnit stuff we don't really care about ...
    ...
12:34:56.999 [main] INFO done

... to just 7 lines:

12:34:56.789 [main] ERROR ..ThingDoer - exception while notifying done listener
java.lang.RuntimeException: listener failed
    at ..ThingDoerTest$DummyListener.onThingDone(:420) ~[tests/:?]
    at ..ThingDoer.doThing(:69) ~[library/:?]
    at com.example.otherproject.Framework.doAllTheThings(:1066)
    at ..ThingDoerTest.listenerException(:666) ~[tests/:?]
    ...
12:34:56.999 [main] INFO done

Let's break that down a bit:

• span gets rid of all the traceback lines coming from JUnit.
• match -v skips some usually useless lines from stack traces.
• sub-paths shortens and highlights the names of classes in the current project; com.example.someproject.somepackage.ThingDoer becomes ..ThingDoer (presumably that's enough info to open the file in your IDE).
• The first sub gets rid of line numbers and JAR names for everything that's not either in the current project or in another com.example. package.
• The second sub gets rid of JAR names for things in other com.example. packages.
• The third sub gets rid of the source file name; ..ThingDoer.doThing(ThingDoer.java:69) becomes ..ThingDoer.doThing(:69) (in Java, the file name matches the class name).

For an even more advanced example, see how to clean up Apache Ant output.

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Anyway, that's it for now.

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