Groovy-Script to count each character in passed file and prints them in ascending order

countEachChar.groovy

#! /usr/bin/env

// Example
// groovy countEachChar.groovy MY_TEXTFILE > OUT_PUT_TEXT_FILE

def printErr = System.err.&println

if (args.length == 0) {
	printErr "No path is passed as an argument! Exiting!"
	return;
}

File file = new File (args[0])

def map = [:]

file.eachLine { line ->
	line.toCharArray().each { c ->
		if (map.containsKey(c)) {
			map.put(c, map[c] + 1)
		} else {
			map.put(c, 1)
		}
	}
}

// asc
map.sort { e1, e2 -> 
	e2.value <=> e1.value
}.each { k, v ->
	println "$k $v"
}

Example output

e 373466
r 243220
i 221312
t 219503
n 216795
a 214619
  175977
s 170042
o 115455