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=== VIM notes 

save: :w
save and exit: :x 

Search forward: /pattern
Search backward ?pattern
Continue forward search n
Continue backward search N 

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Bash / Terminal / Shell notes 
================================
* Script header 
#!/bin/bash

* Decompression: 
$ tar -zxvf filename.tgz 

$ tar -zxvf filename.tar.gz  

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Count the number of the files in your bucket s3cmd ls -r s3://logs.mybucket/subfolder/ | wc -l

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# PythonNotes
## Started Jan, 2015

== String 
s="hello world"
s.replace("hello", "pillo")
s.upper()
b = s.split()
space=" "
space.joib(b) # combines list of strings with spaces in between 

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== Midnight Commander

==== Esc 
Quick change directory: Esc + c
Quick change directory history: Esc + c and then Esc + h
Quick change directory previous entry: Esc + c and then Esc + p
Command line history: Esc + h
Command line previous command: Esc + p
View change: Esc + t (each time you do this shortcut a new directory view will appear)
Print current working directory in command line: Esc + a

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# Read the last 10k lines, then read the 1st 5k lines from that. 
cat myfile | tail -10000 | head -5000 > newfile

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show dbs  // show all the existing dbs on the server.
use db_name // use the db with name 'db_name'
db // name of the db currently being used 
show collections // show information in the db 
db.collection_name.insert({title: 'Hey MongoDB'}) // Creating the collection 'collection_name' and adding an entry to it
db.collection_name.count() // give the count of entries in the collection 
for(var i=0; i < 10; i++) db.collection_name.insert({ number: i }) // loops work in the mongoDB shell! :) 
db.collection_name.find().pretty() // print everything in pretty format inside the 'collection_name'. 
db.collection_name.find({ number: 2 }) // finds the collection with specific definition 
db.collection_name.find().sort({number: 1}) // sorts based on the numbers increasing (in alphabetic order). To ger the reverse we can use {number: -1}

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// more here: https://github.com/scala/pickling 
// note that for each element of the class, there needs to be an implicit function defning pickle/unpickle procedure. 

def pickleCacheToFile(): Unit = {
    println("saving to file ... ")
    val cacheByteArray = objectVar.pickle.value
    val fos = new FileOutputStream(objectVar)
    fos.write(cacheByteArray)
    fos.close()
}

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sortMapByValue(map) {
    var tupleArray = [];
    for (var key in map) tupleArray.push([key, map[key]]);
    tupleArray.sort(function (a, b) {
        return b[1] - a[1]
    });
    var sortedMap = {};
    tupleArray.forEach(function (el) {
        sortedMap[el[0]] = el[1]
    });

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// to Map 
var tupleArray = [[1,2], [3,4]]; 
var outputMap = {};
tupleArray.forEach(function (el) {
    outputMap[el[0]] = el[1]
});

// from Map 
var inputMap = {1: 2, 3: 4}
var tupleArrayOut = Object.keys(inputMap).map(function(e, i){