Common functions for BASH SCRIPT

A Demo to process command line arguments.

#!/bin/bash

# -----------------------------------------------------------------------------
# config item list
# -----------------------------------------------------------------------------
arg1="default value for arg1"
arg2="default value for arg2"
arg3="default value for arg3"

# -----------------------------------------------------------------------------
# functions
# -----------------------------------------------------------------------------
help()
{
  echo "Demo:"
  echo "$ $0 --arg1 'Demo' --arg2 '1.0.0' --arg3 '01'"
  return 0
}

# -----------------------------------------------------------------------------
# config item list
# -----------------------------------------------------------------------------
while [[ $# -ne 0 ]];
do
  case "$1" in
  -h|--help)
    help
    exit 0
  ;;
  --arg1)
    arg1=$2
    shift; shift;
  ;;
  --arg2)
    arg2=$2
    shift; shift
  ;;
  --arg3)
    arg3=$2
    shift; shift
  ;;
  *)
    echo "argument $1 not identified, use -h for help."
    exit 1
  ;;
  esac
done

# -----------------------------------------------------------------------------
# show/use values
# -----------------------------------------------------------------------------
echo "arg1=$arg1"
echo "arg2=$arg2"
echo "arg3=$arg3"

A demo to process log:

#!/bin/bash

LOG_CMD_FLAG=Yes
LOG_FILE=/var/tmp/logcmd.log

logcmd()
{
  case "$LOG_CMD_FLAG" in
  y*|Y*)
    date +"[%Y-%m-%d %H:%M:%S]" | tr -d '\n' >>$LOG_FILE
    echo " Run command [$@]" >>$LOG_FILE
    "$@" >>$LOG_FILE
  ;;
  *)
    return 0
  ;;
  esac
}

logcmd ls --color $HOME
logcmd df -h
logcmd tree .
logcmd ls $HOME
echo "Log file: $LOG_FILE"
echo "============================================================================="
cat $LOG_FILE
echo "============================================================================="