Bash script template

bash-template.sh

#!/usr/bin/env bash

# exit when any command fails
set -e
trap 'echo ''; echo Error at $(basename "$0"):${LINENO}: $BASH_COMMAND' ERR

# Get this script's directory
SDIR="$(dirname "$(realpath "${BASH_SOURCE[0]}")")"






## Optional extras ##

# Change directory to this script's directory
cd "$SDIR"

# Support '**' glob\
shopt -s globstar
shopt -s nullglob

# Check for args
usage() {
    echo "Usage: $(basename -- "$0") ARG"
    exit 1
}
[[ -n "$1" ]] || usage

# Run Windows batch script
batch() {
    local args="$@"
    cmd.exe /c "$args"
}

timestamp()
{
    date "+%Y%m%d-%H%M%S"
}

# Delete everything in `dist/`, but do nothing if empty
# find dist -path 'dist/*' -prune -exec rm -r -- {} +

# Get filename parts
file_ext()
{
    filename=$(basename -- "$1")
    echo "${filename##*.}"
}
basename_no_ext()
{
    filename=$(basename -- "$1")
    echo "${filename%.*}"
}

# Logger
log() {
    echo "[$(date --rfc-3339=seconds)] $@" >> "$SDIR/log.txt"
    echo "$@"
}

logerr() {
    log "ERROR" "$@"
    return 1
}

# Find 7z (Windows)
if ! type 7z 2> /dev/null && [ -e "/c/Program Files/7-Zip/7z.exe" ]; then
    PATH="$PATH:/c/Program Files/7-Zip/"
fi
# 7z a -tzip archive.zip *

# Progress bar animation
draw_progress_bar() {
    local value=$1
    local max=$2
    local msg=${3:-""}
    local bar_width=${4:-50}

    if [[ -z "$COLUMNS" ]]; then
        COLUMNS="$(tput cols)"
    fi

    if [[ -z "$MSG_PADDING" ]]; then
        MSG_PADDING="                                                         "
    fi

    if [[ -n "$msg" ]]; then msg=" $msg"; fi

    # Calculate percentage
    if (( $max < 1 )); then max=1; fi  # anti zero division protection
    local percentage=$(( 100 - (max*100 - value*100) / max ))

    # Rescale the bar according to the progress bar width
    local num_bar=$(( percentage * bar_width / 100 ))

    # Draw progress bar
    local bar_str="["
    for b in $(seq 1 $num_bar); do bar_str+="#"; done
    for s in $(seq 1 $(( bar_width - num_bar ))); do bar_str+=" "; done
    bar_str+="] $percentage%$msg$MSG_PADDING"

    printf '%.*s\r' $((COLUMNS - 1)) "$bar_str"
}