remove_old

#!/bin/bash

# removes all but the latest N files

shopt -s extglob
# default variable values
to_keep=10
to_prompt=0
verbose=0
dotfiles=0
user_max=0
has_max=1
max=1
follow=0
force=0
confirm=1

usage() {
cat <<'EOF'
remove_old [OPTION]... [DIR]...

Removes all but the latest N files in DIR(s).
If no DIR is supplied, use current working directory.
If DIR is '-', read list of dirs from stdin, one per line.

 Options:
  -h, --help	     Display this prompt and exit.
  -n, --num NUM      Keep NUM files. default is 10.
  -r, --recurse      Remove files recursively.
  -L, --follow       Follow symlinks when recursing. By default, they will not
                     be followed and instead will be ignored
  -m, --max NUM      Only recurse NUM levels (implies -r)
  -f, --force        Force removal of files (rm -f)
  -d, --dotfiles     Remove dotfiles as well.
  -i, --interactive  Prompt before removal of every file.
  -a, --no-confirm   Do not display a confirmation prompt before removing.
                     By default, a prompt is printed before processing each
                     DIR
  -v, --verbose	     Display more info.

Requires GNU find and sort.
EOF
}

# usage: confirm PROMPT
# yes/no prompt, returns according to the user's response
confirm() {
  local -l reply

  read -p "$1 [y/N] " reply
  [[ $reply = y?(es) ]]
}

# usage: get_files DIR [FIND_OPTIONS]
# run the find command, using the arguments beyond "$1" as options to find
# determines whether or not to follow symlinks based on -f, --follow
get_files() {
  if ((follow)); then
    find -L "$@" -type f -printf '%T@ %p\0' | sort -znr
  else
    find "$@" -type f -printf '%T@ %p\0' | sort -znr
  fi
}

# display error and exit with failure
die() {
  printf '%s\n' "$@" >&2
  exit 1
}

# option string, for short options.
# very much like getopts, any option followed by a ':' takes a required arg
optstring=hn:rLm:fdiav

# iterate over options, breaking -ab into -a -b and --foo=bar into --foo bar
# also turns -- into --endopts to avoid issues with things like -o-, the '-'
# should not be an end of options, but an invalid option
unset options
while (($#)); do
  case $1 in
    # if option is of type -ab
    -[!-]?*)
      # loop over each character starting with the second
      for ((i=1; i<${#1}; i++)); do
        c=${1:i:1}
        
        # add current char to options
        options+=("-$c")

        # if option takes a required argument, and it's not the last char
        # make the rest of the string its argument
        if [[ $optstring = *"$c:"* && ${1:i+1} ]]; then
          options+=("${1:i+1}")
          break
        fi
      done
      ;;
    # if option is of type --foo=bar, split on first '='
    --?*=*) options+=("${1%%=*}" "${1#*=}");;
    # end of options, stop breaking them up
    --)
      options+=(--endopts)
      shift
      options+=("$@")
      break
      ;;
    # otherwise, nothing special
    *) options+=("$1");;
  esac

  shift
done
# set new positional parameters to altered options
set -- "${options[@]}"
unset options

# parse options
while [[ $1 = -?* ]]; do
  case $1 in
    -h|--help) usage >&2; exit 0;;
    -n|--num)
      # make sure NUM is a valid int
      [[ $2 && $2 != *[!0-9]* ]] || die "invalid number: $2"
      to_keep=$2
      shift
      ;;
    -r|--recurse)
      if ((!user_max)); then
        has_max=0
      fi
      ;;
    -L|--follow) follow=1;;
    -m|--max)
      # make sure NUM is a valid int
      [[ $2 && $2 != *[!0-9]* ]] || die "invalid number: $2"
      user_max=1
      has_max=1
      max=$2
      shift
      ;;
    -f|--force) force=1;;
    -d|--dotfiles) dotfiles=1;;
    -i|--interactive) to_prompt=1;;
    -a|--no-confirm) confirm=0;;
    -v|--verbose) verbose=1;;
    --endopts) shift; break;;
    *) die "invalid option: $1"
  esac

  shift
done

# populate array of dirs to use
if (($#)); then
  dirs=()
  for dir; do
    # if target is '-', read list from stdin
    if [[ $dir = - ]]; then
      while read -r line; do
	dirs+=("$line")
      done
      
      # make stdin the terminal again for rm prompting
      exec </dev/tty

    # if dir exists, add it to array
    elif [[ -d $dir ]]; then
      dirs+=("$dir")

    # otherwise err
    else
      printf '%s does not exist or is not a directory, skipping\n' "$dir" >&2
    fi
  done

# if no dirs specified, use '.'
else
  dirs=(.)
fi

# set rm command
if ((to_prompt)); then
  rm=(rm -i)
else
  rm=(rm)
fi
if ((force)); then
  rm+=(-f)
fi

# set recursion, whether or not to ignore dotfiles/dirs
findopts=()
if ((has_max)); then
  findopts+=(-maxdepth "$max")
fi
if ((!dotfiles)); then
  findopts+=(\( -name '.*' ! -name '.' \) -prune -o)
fi

# loop over each dir provided, remove old files
for dir in "${dirs[@]}"; do
  if ((confirm)); then
    confirm "Remove all files except the $to_keep latest from $dir?" ||
      continue
  fi
  if ((verbose)); then
    printf 'Processing dir: %s\n' "$dir"
  fi
  
  i=0
  while { read -rd ' ' t; IFS= read -rd '' f; } <&3; do
    if ((++i > to_keep)); then
      if ((verbose)); then
        printf 'Removing file: "%s" with mtime: "%s"\n' \
               "$f" "$(date -d "@${t%.*}" +'%F %H:%M:%S')"
      fi

      "${rm[@]}" "$f"
    fi
  done 3< <(get_files "$dir" "${findopts[@]}")
done



# Copyright Daniel Mills <dm@e36freak.com>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.