Tutorial by Examples: com

Execute some Perl code from command line

Simple one-liners may be specified as command line arguments to perl using the -e switch (think "execute"): perl -e'print "Hello, World!\n"' Due to Windows quoting rules you can't use single-quoted strings but have to use one of these variants: perl -e"print qq(Hello, W...

Perl Language • Perl one-liners

Organizing Component Layout

Adding components one after another results in a UI that's hard to use, because the components all are somewhere. The components are ordered from top to bottom, each component in a separate "row". To remedy this and provide you as developer with a possibility to layout components easily S...

swing • Using Swing for Graphical User Interfaces

Curl Command for counting number of documents in the cluster

curl -XGET 'http://www.example.com:9200/myIndexName/_count?pretty' Output: { "count" : 90, "_shards" : { "total" : 6, "successful" : 6, "failed" : 0 } } The index has 90 documents within it. Reference Link: Here

Elasticsearch • Curl Commands

Connect To A Database on *.meteorapp.com

The --url flag can be tricky to use. There is a 60 second window to authenticate, and then the username/password randomly resets. So be sure to have robomongo open and ready to configure a new connection when you run the command. # get the MONGO_URL string for your app meteor mongo --url $METEOR...

meteor • Mongo Database Management

Download a Database from *.meteor.com

Same thing as before, but you have to copy the info into the mongodump command. You have to run the following commands rediculously fast, and it requires hand/eye coordination. Be warned! This is a rediculously hacky! But fun! Think of it as a video game! :D # get the MONGO_URL string for your app ...

meteor • Mongo Database Management

Compact a Mongo Database on an Ubuntu Box

Preallocation. Mongo sets aside disk-space in empty containers, so when the time comes to write something to disk, it doesn't have to shuffle bits out of the way first. It does so by a doubling algorithm, always doubling the amount of disk space preallocated until it reaches 2GB; and then each preal...

meteor • Mongo Database Management

Connect Remotely to a Mongo Instance on *.meteor.com

Did you know about the --url flag? Very handy. meteor mongo --url YOURSITE.meteor.com

meteor • Mongo Database Management

"Hello world!" with common command line options

For programs with a single source file, using gcc is simple. /* File name is hello_world.c */ #include <stdio.h> int main(void) { int i; printf("Hello world!\n"); } To compile the file hello_world.c from the command line: gcc hello_world.c gcc will then compil...

gcc • Getting started with gcc

Common control sequences in format strings

While there are many different control sequences for io:format and io_lib:format, most of the time you'll use only three different ones: ~s, ~p and ~w. ~s The ~s is for strings. It prints strings, binaries and atoms. (Anything else will cause a badarg error.) It doesn't quote or escape anything...

Erlang Language • Format Strings

Show a git branch using PROMPT_COMMAND

If you are inside a folder of a git repository it might be nice to show the current branch you are on. In ~/.bashrc or /etc/bashrc add the following (git is required for this to work): function prompt_command { # Check if we are inside a git repository if git status > /dev/null 2>&a...

Bash • Customizing PS1

Convert NSDate that is composed from hour and minute (only) to a full NSDate

There are many cases when one has created an NSDate from only an hour and minute format, i.e: 08:12 The downside for this situation is that your NSDate is almost completely "naked" and what you need to do is to create: day, month, year, second and time zone in order to this object to &quo...

Objective-C Language • NSDate

Calling a Tcl command from an expression

Sometimes you need to call a Tcl command from your expression. For example, supposing you need the length of a string in it. To do that, you just use a [...] sequence in the expression: set halfTheStringLength [expr { [string length $theString] / 2 }] You can call any Tcl command this way, but i...

tcl • Expressions

D3.js component with ReactJS

This example is based on a blog post by Nicolas Hery. It utilizes ES6 classes and ReactJS's lifecycle methods to keep the D3 component updated d3_react.html <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Hello, d3React!</title>...

d3.js • Using D3 with other frameworks

Commit ancestry chain: ^, ~, etc.

$ git reset --hard HEAD^ # discard last commit $ git rebase --interactive HEAD~5 # rebase last 4 commits A suffix ^ to a revision parameter means the first parent of that commit object. ^<n> means the <n>-th parent (i.e. <rev>^ is equivalent to <rev>^1). A...

Git • Git revisions syntax

Youngest matching commit: ^{/}, :/

$ git show HEAD^{/fix nasty bug} # find starting from HEAD $ git show ':/fix nasty bug' # find starting from any branch A colon (':'), followed by a slash ('/'), followed by a text, names a commit whose commit message matches the specified regular expression. This name returns the younge...

Git • Git revisions syntax

Compiling on Ubuntu

To build vim from source on Ubuntu: Get a copy of the source code by downloading from the official Vim repository on GitHub. Get the dependencies by running $ sudo apt-get build-dep vim-gnome or similar. Go to the directory of the Vim source code: cd vim/src Run $ ./configure. You can customiz...

vim • How to Compile Vim

With paste command

# Process substitution with paste command is common # To compare the contents of two directories paste <( ls /path/to/directory1 ) <( ls /path/to/directory1 )

Bash • Process substitution

Generating Random number using apache-common lang3

We can use org.apache.commons.lang3.RandomUtils to generate random numbers using a single line. int x = RandomUtils.nextInt(1, 1000); The method nextInt(int startInclusive, int endExclusive) takes a range. Apart from int, we can generate random long, double, float and bytes using this class. R...

Java Language • Random Number Generation

Comparison Operators

OperatorDescription==true if the two values are equal.!=true if the two values are not equal.<true if the value of the operand on the left is less than the value on the right.>true if the value of the operand on the left is greater than the value on the right.>=true if the value of the oper...

Ruby Language • Operators

One way parent-child communication

Example demonstrates component composition and one-way message passing from parent to children. 0.18.0 Component composition relies on Message tagging with Html.App.map 0.18.0 In 0.18.0 HTML.App was collapsed into HTML Component composition relies on Message tagging with Html.map Example ...

Elm Language • The Elm Architecture