Generate a bar chart by reading value/label pairs from stdin

README.md

Bar charts from stdin

Put this shell script somewhere in your path and run it by feeding it value/label pairs like this:

$ bars
10 one
20 two
30 three
^D

And you'll get something like this:

10   one ################
20   two ################################
30 three #################################################

Value comes first because labels are optional. If you're data is the other way round, just use awk before bars:

$ awk '{ print $2 $1 }' < your_data | bars

Examples

Get a bar chart of word frequencies in a text file:

$ tr -sc 'A-Za-z' '\012' < textfile | sort | uniq -c | sort -nr | bars

Get a bar chart of file sizes:

$ du -hk * | bars

Show a chart of total lines per file:

$ wc -l * | bars

Use another character for the bars:

$ BARCHAR='*' bars

Pad values to have fixed width:

$ VMAX=8 bars

bars.sh

#!/usr/bin/env bash

# Generate a bar chart by reading value/label pairs from stdin
bars() {
	local VALUES=() LABELS=()
	local EOL=${EOL:-$'\n'} MAX=${BARMAX:-0} VMAX=${VMAX:-0} LMAX=${LMAX:-0}
	local N=0 V L LN

	while read -r V L
	do
		(( V > MAX )) && MAX=$V

		VALUES[$N]=$V
		LABELS[$N]=$L
		(( ++N ))

		LN=${#L}
		(( LN > LMAX )) && LMAX=$LN

		LN=${#V}
		(( LN > VMAX )) && VMAX=$LN
	done

	local COUNT=$N COLUMNS=${COLUMNS:-$(tput cols)}
	local HC=$(( COLUMNS/2 ))
	(( LMAX > HC )) && LMAX=$(( HC ))

	local BARCHAR=${BARCHAR:-#}
	local BMAX=$(( COLUMNS-LMAX-VMAX-1 ))
	local BAR='' LSPACE=''

	if (( LMAX > 0 ))
	then
		(( --BMAX ))
		LSPACE=' '
	fi

	while (( ${#BAR} < BMAX ))
	do
		BAR=$BAR${BAR:-$BARCHAR}
	done

	local F=$(( (MAX<<16)/BMAX ))
	(( F < 1 )) && F=1

	for (( N = 0; N < COUNT; ++N ))
	do
		L=${LABELS[$N]}
		(( ${#L} > LMAX )) && L='...'${L:$(( ${#L}-LMAX+3 ))}

		printf "%${VMAX}d %${LMAX}s%s%s$EOL" \
			"${VALUES[$N]}" \
			"$L" \
			"$LSPACE" \
			"${BAR:0:$(( (${VALUES[$N]}<<16)/F ))}"
	done
}

if [ "${BASH_SOURCE[0]}" == "$0" ]
then
	bars
fi

tests.sh

#!/usr/bin/env bash

test_single_line() {
	for (( N = 0; N <= RANGE; ++N ))
	do
		echo "$N" | BARMAX=$RANGE ./bars
	done
}

test_multi_line() {
	for (( N = 0; N <= RANGE; ++N ))
	do
		echo "$N"
	done | BARMAX=$RANGE ./bars
}

test_multi_line_alt_char() {
	BARCHAR='=' test_multi_line
}

test_custom_width() {
	COLUMNS=60 test_multi_line
}

test_progress_bar() {
	for (( MAX=100, N = 0; N <= MAX; N += 5 ))
	do
		echo "$N" '%' | VMAX=3 BARMAX=$MAX EOL=$'\r' ./bars
		sleep 1
	done
	echo
}

test_long_labels() {
	du -hk "$(cd "${0%/*}" && echo "${PWD%/*}")"/* | ./bars
}

test_with_total() {
	wc -l "${0%/*}"/* | ./bars
}

test_word_frequency() {
	tr -sc 'A-Za-z' '\012' < "$0" | sort | uniq -c | sort -nr | ./bars
}

readonly RANGE=${RANGE:-20}

if (( $# > 0 ))
then
	for TEST in "$@"
	do
		$TEST
	done
else
	grep '^test_' "$0" | while read -r TEST
	do
		TEST=${TEST%%(*}
		$TEST
	done
fi