A --help argument would help

Open Beginner friendly

#28 opened on May 4, 2015 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 2/5
Estimated time: 1-3 hours
Newbie friendliness: 62/100

Issue type: Bug
Clarity: Mostly clear
Activity status: Stale
Tech stack: java
Domain: cli

Research direction

Start at com.jvmtop.JvmTop.main in JvmTop.java around line 122, where the reported NumberFormatException occurs. Run ./jvmtop.sh --help and try an unknown argument to compare the current behavior with the requested usage output. Done means --help displays the options and examples instead of failing, while invalid arguments still provide useful guidance.

Written by the indexing model from the issue text.

Description

auto-migrated Priority-Medium Type-Enhancement

What steps will reproduce the problem?
1. ./jvmtop.sh --help

jvmtop has several arguments that can only be learned through looking at a few 
different pages in the wiki - since there is no source code, hard to know if 
they are all documented anywhere.

What is the expected output? What do you see instead?

[me@localhost~]$ jvmtop --help

JvmTop 0.7.1 alpha, http://code.google.com/p/jvmtop
Usage: info [OPTIONS]... [PID]

Monitor JVM metrics on the command line

Options (only one can be specified):
  --help                this text
  --once  [PID]      Run jvmtop one time, then exit
  --delay N           Delay N seconds between updates
  --profile PID      Profile a specifc JVM instance

Examples:
   jvmtop             Summarize all currently running JVM's
   jvmtop 3944    Display detailed information for a single JVM (pid #3944)
   jvmtop --delay 3 --profile 3944
                           Profile process #3944, updating the display every 3 seconds

Plus appending what you currently have written up for the column definitions on 
the ExampleOutput wiki page would be a nice touch.  


or for an unknown argument:

[me@localhost~]$ jvmtop --foo
jvmtop: unrecognized option '--foo'
Try --help for more information.


Actual:
[me@localhost~]$ jvmtop --help
Exception in thread "main" java.lang.NumberFormatException: For input string: 
"--help"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:492)
    at java.lang.Integer.parseInt(Integer.java:527)
    at com.jvmtop.JvmTop.main(JvmTop.java:122)

Original issue reported on code.google.com by DaveParillo on 8 Aug 2013 at 11:49

Dominant language: Java
Stars: 5
Forks: 2
PR merge metrics: No merged PRs in 30d

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