Bash Idioms template

sh

#!/bin/bash
#jbenninghoff 2015-Dec-28  vi: set ai et sw=3 tabstop=3 retab:

: << '--BLOCK-COMMENT--'
Bash idioms template
Save as ~/.vim/templates/sh
Above requires vim templates plugin: https://github.com/ap/vim-templates
Useful site for lots of Bash info: http://wiki.bash-hackers.org/
--BLOCK-COMMENT--

# Check for root
[ $(id -u) -ne 0 ] && { echo This script must be run as root; exit 1; }

# Make temp file, delete when script ends
tmpfile=$(mktemp); trap 'rm $tmpfile' 0 1 2 3 15

#Pause the script
read -s -r -p "Press enter to continue or ctrl-c to abort"

sep='====================================================================='
# Pad $msg to fixed length using $sep
msg="Job Status"; printf "%s %s \n" "$msg" "${sep:${#msg}}"

# Handle script arguments
verbose=false
while getopts ":v" opt; do
  case $opt in
    v) verbose=true ;;
    \?) echo "Invalid option: -$OPTARG" >&2; exit ;;
  esac
done

# Assign file contents to shell variable
[ -f myIPlist ] && hosts=$(<myIPlist)
#Assign 6 args to single variable
[ $# -gt 0 ] && hosts="$1 $2 $3 $4 $5 $6"

# Various for loops
#for i in $hosts; do
#for ((i=8; i>0; i--)); do
#for i in {1..5}; do
for i in $(seq 1 $nproc); do
   echo $i
done

# Locate next smallest power of 2 using bitwise AND
n=$1
while ((n & (n - 1))); do
   ((n--))
done

# Repeat command until string found
until (maprcli dump rereplicationinfo | grep 'No active rereplications'); do
   echo -n 'Still Replicating '; sleep 120
done

# Use a shell array variable; declare, assign, append
declare -A maclist
maclist[10.20.30.44]=00:21:9b:a1:17:63
maclist+=( [10.20.30.40]=00:21:9b:a1:17:62 )
maclist+=( [10.20.30.48]=00:21:9b:9e:ae:15 )
# Loop over contents of shell array
for key in ${!maclist[@]}; do
   echo ${key} ${maclist[${key}]}
done

echo $[10*1000*1000]
# filename=${path##*/}
# dirname=${path%/*}
# printf "%c" {a..z} $'\n' #Print the alphabet and newline using bash quoting $'...'
# IFS=- read -r x y z <<< "str=foo-bar-baz" #read doesn't work with pipe|