Log output of a command to both a file and the console.

logf.sh

#!/bin/bash

# Function to show usage
usage() {
	echo "logf: A script to execute a command and log its output to both a file and the console."
	echo
	echo "Usage: $0 [-a] <logfile> <command> [args...]"
	echo "  -a  Append to the logfile instead of overwriting"
	exit 1
}

# Check if there are at least two arguments
if [ "$#" -lt 2 ]; then
	usage
fi

# Check for the -a option
APPEND=false
if [ "$1" == "-a" ]; then
	APPEND=true
	shift
	# Check again if there are at least two arguments after shifting
	if [ "$#" -lt 2 ]; then
		usage
	fi
fi

# Extract the logfile parameter
LOGFILE=$1
shift

# Set the tee command based on the append option
if $APPEND; then
	TEE_CMD="tee -a"
else
	TEE_CMD="tee"
fi

# Execute the command and log output to both the logfile and the console
"$@" 2>&1 | $TEE_CMD "$LOGFILE"

# Exit with the command's exit code
exit ${PIPESTATUS[0]}