#!/usr/bin/env sh
# backup, timestamped
# compat: +ash +bash +dash +zsh

baks() { ### @-
    ### backup files by copying each and appending *the current* date-time,
    ### irrespective of when the files were modified or created.
    ###
    ### ```
    ### $ touch -d '2001-12-25 16:30:00' butts
    ### $ baks butts
    ### $ baks butts
    ### $ ls -l
    ### total 0
    ### -rw-r--r-- 1 notwa None 0 Dec 25  2001 butts
    ### -rw-r--r-- 1 notwa None 0 Dec 25  2001 butts.21-08-01_14-54-07.bak
    ### -rw-r--r-- 1 notwa None 0 Dec 25  2001 butts.21-08-01_14-54-09.bak
    ### ```
    local ret=0 fp=
    for fp; do
        local now="$(date -u '+%y-%m-%d_%H-%M-%S')"
        local bak="$fp.$now.bak"
        if [ -s "$bak" ]; then
            #note "how in the hell?" "$bak" "already exists"
            printf "%s %s %s\n" "how in the hell?" "$bak" "already exists"
            ret=1
        fi
        cp -p "$fp" "$bak" || ret=1
    done
    return $ret
}

[ -n "${preload+-}" ] || . ~/sh/preload || exit 2
eval ${preload:-preload} note
[ -n "${preload+-}" ] || baks "$@"