cpu-usage

#!/usr/bin/env bash
#
# 2020 Toazd cpu_usage.sh
#
# Purpose:
#   Parse mpstat output (the last line - avg idle%) and convert it to usage%
#   Requires mpstat (sysstat)
#
################################################################################

iINTERVAL=1
iREPORTS=1
sAVG_LINE=""

# map the output of mpstat into an indexed array
mapfile -s 2 -t <<< "$(mpstat $iINTERVAL $iREPORTS --dec=2)"

# we only want the last line which is the same no matter how many reports are chosen (index total - 1)
sAVG_LINE=${MAPFILE[${#MAPFILE[@]}-1]}

# remove all spaces including anything to the left of them
sAVG_LINE=${sAVG_LINE##* }

# round to 0 decimals (to avoid showing extraneous zeros *.0%), left bound the field (aligns better with icons/glyphs)
sCPU_USAGE=$(printf '%-.0f' "$(bc -l <<< 100-"${sAVG_LINE}")")%

if [[ ${sCPU_USAGE:0:1} -eq 0 ]]
then
    printf '%s\n' "<1%"
else
    printf '%s\n' "$sCPU_USAGE"
fi