How do I append a date to a file using Bash script with multiple variables?

Question

My script is below, I can't remember how to make this make sense.

#!/bin/bash
input=$1
output=$2
cp $input $output_$(date +%m%d%y)

The goal is to run the script as follows

/path/script.sh /path/file_name /path/archive/

Archived file would then be /path/archive/file_name_090718

Answer 1

Wrapping ${output} in {} brackets allows the concatenation of the underscore and date. Alternatively you could just use cp $1 $2_$(date +%m%d%y).

script.sh

#!/bin/bash
input=$1
output=$2
cp ${input} ${output}_$(date +%m%d%y)

Usage:

$ ls
file_name script.sh
$./script.sh file_name archive
$ ls
archive_090718 file_name script.sh

Answer 2

THE ANSWER IS CURLY BRACKETS!

This is how I did it; it's not the prettiest way to skin a cat...

#!/bin/bash
input=$1
output=$2
cp $input ${output}_$(date +%m%d%y)

$ ./script /usr/tmp/file_name /usr/tmp/arch/file_name

$ ls -l /usr/tmp/arch
-rw-rw-r-- 1 xxxxxx yyyyyyy 5 Sep  7 12:06 file_name_090718