How to use tar with an argument in the path - bash

Question

I am trying to tar some files into a destination, where FILES path and DESTINATION were entered as arguments ($1 and $2): script FILE DEST
I want to tar the files into the destination and change the name (ex: add the word "update" and the date at the end of the filename) at the end of the new tar file
So I have: date=date dest=$2 files="$1/*" #considers all the files within the directory given, as files is a . directory containing one or more files tar $dest/"update"$date $files
however, this does not work, and I get the error: tar: Old option 'u' requires an argument (as in the u in "update" I assume)

Answer 1

It is a little unclear from your description, but it appears you are trying to make a script that will take a directory name you call FILE as the first argument and then a name for your archive as the second argument you call DEST to which you want to append "_update_$(date +%F).tar.xz" (or choose the compression type you wish). You then want to create a TAR archive similar to:
tar -cJf "${2}_update_$(date +%F).tar.xz" "$1"/*
A script to do that is relatively straight forward, and we will add the -J option to use xz compression for the archive. Your FILE and DEST names are confusing, so let's use dname for the directory containing the files and tarname for the archive name. The after appending "_update_$(date +%F).tar.xz" to your tarname input you could do:
#!/bin/bash
[ -z "$1" ] || [ -z "$2" ] && { ## validate 2 arguments given
printf "error: insufficient input\nusage: %s file dest\n" "${0##*/}" >&2
exit 1
}
dirname="$1" ## name of directory to archive
tarname="${2}_update_$(date +%F).tar.xz" ## archive name
tar -cJf "$tarname" "$dirname"/* ## create compressed archive
Example Directory to Archive
$ ls -al tmpd/
total 4
drwxr-xr-x 2 david david 180 Sep 26 11:15 .
drwxrwxrwt 20 root root 420 Sep 26 11:16 ..
-rw-r--r-- 1 david david 0 Sep 26 11:15 a
-rw-r--r-- 1 david david 0 Sep 26 11:15 b
-rw-r--r-- 1 david david 0 Sep 26 11:15 c
-rw-r--r-- 1 david david 0 Sep 26 11:15 d
-rw-r--r-- 1 david david 0 Sep 26 11:15 e
-rw-r--r-- 1 david david 0 Sep 26 11:15 f
-rw-r--r-- 1 david david 111 Sep 22 22:08 file
Example Use/Output
$ bash quicktar.sh tmpd myfiles
The archive is created:
$ ls -al myfiles_update_2019-09-26.tar.xz
-rw-r--r-- 1 david david 460 Sep 26 11:16 myfiles_update_2019-09-26.tar.xz
Finally check the content of the compressed archive:
$ tar -tJf myfiles_update_2019-09-26.tar.xz
tmpd/a
tmpd/b
tmpd/c
tmpd/d
tmpd/e
tmpd/f
tmpd/file
Look things over and let me know if that is what you intended. You can drop compression or change the type just by changing the -J option in the command above.