Simple database
Write a simple tool to track a small set of data. The tool should have a commandline interface to enter at least two different values. The entered data should be stored in a structured format and saved to disk.
It does not matter what kind of data is being tracked. It could be your CD collection, your friends birthdays, or diary.
You should track the following details:
- A description of the item. (e.g., title, name)
- A category or tag (genre, topic, relationship such as “friend” or “family”)
- A date (either the date when the entry was made or some other date that is meaningful, like the birthday); the date may be generated or entered manually
- Other optional fields
The command should support the following Command-line arguments to run:
- Add a new entry
- Print the latest entry
- Print the latest entry for each category
- Print all entries sorted by a date
The category may be realized as a tag or as structure (by making all entries in that category subitems)
The file format on disk should be human readable, but it need not be standardized. A natively available format that doesn't need an external library is preferred. Avoid developing your own format however if you can use an already existing one. If there is no existing format available pick one of: JSON, S-Expressions, YAML, or others.
See also Take notes on the command line for a related task.
Common Lisp
A tool to track the episodes you have watched in a series. Tested with SBCL but should work with other implementations.
Run from the commandline as:
sbcl --script watch.lisp
Without arguments the function (watch-list) is invoked to show the last episode of each series.
With the argument add the function (watch-add) will allow you to add a new episode with series name, episode title, episode number and date watched. If the series does not yet exist, you will be asked if you want to create it.
This code is also available under the GNU GPLv3. <lang lisp>(defvar db nil)
(defun make-episode (&key series title episode date)
`((series . ,series) (episode . ,episode) (title . ,title) (date . ,date)))
(defun print-episode (episode)
(format t " ~30a ~10a ~30a (~{~a~^.~})~%"
(cdr (assoc 'series episode)) (cdr (assoc 'episode episode))
(cdr (assoc 'title episode)) (cdr (assoc 'date episode))))
(defun print-episodes (episodes series)
(or (null episodes)
(print-episode (acons 'series-name series (car episodes)))
(print-episodes (cdr episodes) series)))
(defun get-latest (database)
(cond ((endp database) nil)
(T (cons (cadr (assoc 'episodes (cdar database))) (get-latest (cdr database))))))
(defun compare-date (a b)
(cond ((not (and (listp a) (listp b))) nil)
((null a) (not (null b)))
((null b) nil)
((= (first a) (first b)) (compare-date (rest a) (rest b)))
(t (< (first a) (first b))) ))
(defun compare-by-date (a b)
(compare-date (reverse (cdr (assoc 'date a))) (reverse (cdr (assoc 'date b)))))
(defun prompt-read (prompt &optional (default ""))
(format *query-io* "~a (~a): " prompt default)
(force-output *query-io*)
(let ((answer (read-line *query-io*)))
(if (string= answer "") default answer)))
(defun split (seperator string)
(loop for i = 0 then (1+ j)
as j = (search seperator string :start2 i)
collect (subseq string i j)
while j))
(defun parse-date (date)
(mapcar #'parse-integer (split "." date)))
(defun prompt-for-episode (&optional last)
(make-episode
:series (prompt-read "Series Title" (cdr (assoc 'series last)))
:title (prompt-read "Title")
:episode (prompt-read "Episode")
:date (parse-date (prompt-read "Date watched"))))
(defun save-db (filename database)
(let ((file (probe-file filename)))
(rename-file file (concatenate 'string (file-namestring file) ",1"))
(with-open-file (out file
:direction :output
:if-exists :supersede)
(with-standard-io-syntax
(let ((*print-case* :downcase))
(pprint database out))))))
(defun watch-save ()
(save-db "lwatch" db))
(defun load-db (filename)
(with-open-file (in filename)
(with-standard-io-syntax
(read in))))
(defun get-series (name database)
(cdr (assoc name database :test #'equal)))
(defun get-episode-list (series database)
(cdr (assoc 'episodes (get-series series database))))
(defun print-series (series)
(format t "~30a ~10a~%" (cdr (assoc 'series series)) (cdr (assoc 'status series))) (mapcar #'print-episode (cdr (assoc 'episodes series))))
(defun watch-series (title)
(let ((series (get-series title db))) (format t "~30a ~10a~%" (cdr (assoc 'series series)) (cdr (assoc 'status series))) (mapcar #'print-episode (reverse (cdr (assoc 'episodes series))))))
(defun dump-db (database)
(dolist (series database) (print-series (cdr series))))
(defun watch-latest ()
(mapcar #'print-episode (sort (get-latest db) #'compare-by-date)))
(defun watch-new-series (name status)
(cdar (push `(,name (series . ,name) (status . ,status) (episodes)) db)))
(defun get-or-add-series (name database)
(or (get-series name database)
(if (y-or-n-p "Add new series? [y/n]: ")
(watch-new-series name 'active) nil)))
(defun watch-add ()
(let* ((series (loop thereis (get-or-add-series (prompt-read "Series") db)))
(episodes (cdr (assoc 'episodes series)))
(episode (prompt-for-episode (car episodes))))
(rplacd (assoc 'episodes series)
(cons episode episodes))))
(defun watch-series-names ()
(format T "~{~a~%~}"
(sort (mapcar #'car db)
#'(lambda (series1 series2)
(compare-by-date (cadr (assoc 'episodes (cdr (assoc series1 db))))
(cadr (assoc 'episodes (cdr (assoc series2 db)))))))))
(defun watch-load ()
(setf db (load-db "lwatch")))
(defun argv ()
(or #+clisp (ext:argv) #+sbcl sb-ext:*posix-argv* #+clozure (ccl::command-line-arguments) #+gcl si:*command-args* #+ecl (loop for i from 0 below (si:argc) collect (si:argv i)) #+cmu extensions:*command-line-strings* #+allegro (sys:command-line-arguments) #+lispworks sys:*line-arguments-list* nil))
(defun main (argv)
(watch-load)
(cond ((equal (cadr argv) "add") (watch-add) (watch-save))
((equal (cadr argv) "latest") (watch-latest))
((null (cadr argv)) (watch-latest))
((equal (cadr argv) "series") (watch-series-names))
(T (watch-series (cadr argv)))))
(main (argv))</lang>
PicoLisp
The 'rc' resource file handling function is used typically for such tasks. It also takes care of proper locking and protection. <lang PicoLisp>#!/usr/bin/pil
(de usage ()
(prinl
"Usage:^J\
sdb <file> add <title> <cat> <date> ... Add a new entry^J\
sdb <file> get <title> Retrieve an entry^J\
sdb <file> latest Print the latest entry^J\
sdb <file> categories Print the latest for each cat^J\
sdb <file> Print all, sorted by date" ) )
(de printEntry (E)
(apply println (cdddr E) (car E) (cadr E) (datStr (caddr E))) )
(ifn (setq *File (opt))
(usage)
(case (opt)
(add
(let (Ttl (opt) Cat (opt))
(if (strDat (opt))
(rc *File Ttl (cons Cat @ (argv)))
(prinl "Bad date") ) ) )
(get
(let Ttl (opt)
(when (rc *File Ttl)
(printEntry (cons Ttl @)) ) ) )
(latest
(printEntry (maxi caddr (in *File (read)))) )
(categories
(for Cat (by cadr group (in *File (read)))
(printEntry (maxi caddr Cat)) ) )
(NIL
(mapc printEntry (by caddr sort (in *File (read)))) )
(T (usage)) ) )
(bye)</lang> Test:
$ sdb CDs add "Title 1" "Category 1" 2011-11-13 $ sdb CDs add "Title 2" "Category 2" 2011-11-12 $ sdb CDs add "Title 3" "Category 1" 2011-11-14 foo bar $ sdb CDs add "Title 4" "Category 2" 2011-11-15 mumble $ sdb CDs get "Title 3" "Title 3" "Category 1" "2011-11-14" "foo" "bar" $ sdb CDs latest "Title 4" "Category 2" "2011-11-15" "mumble" $ sdb CDs categories "Title 4" "Category 2" "2011-11-15" "mumble" "Title 3" "Category 1" "2011-11-14" "foo" "bar" $ sdb CDs "Title 2" "Category 2" "2011-11-12" "Title 1" "Category 1" "2011-11-13" "Title 3" "Category 1" "2011-11-14" "foo" "bar" "Title 4" "Category 2" "2011-11-15" "mumble"
Pike
<lang Pike>mapping db = ([]);
mapping make_episode(string series, string title, string episode, array date) {
return ([ "series":series, "episode":episode, "title":title, "date":date ]);
}
void print_episode(mapping episode) {
write(" %-30s %10s %-30s (%{%d.%})\n",
episode->series, episode->episode, episode->title, episode->date);
}
void print_series(mapping series) {
write("%-30s %-10s\n", series->series, series->status);
map(series->episodes, print_episode);
}
void dump_db(mapping database) {
foreach(database; string name; mapping series)
{
print_series(series);
}
}
array get_latest(mapping database) {
array latest = ({});
foreach(database; string name; mapping series)
{
latest += ({ series->episodes[0] });
}
return latest;
}
int(0..1) compare_date(array a, array b) {
if (!arrayp(a) && !arrayp(b)) return false; if (!arrayp(a) || !sizeof(a)) return arrayp(b) && sizeof(b); if (!arrayp(b) || !sizeof(b)) return arrayp(a) && sizeof(a); if (a[0] == b[0]) return compare_date(a[1..], b[1..]); return a[0] < b[0];
}
int(0..1) compare_by_date(mapping a, mapping b) {
return compare_date(reverse(a->date), reverse(b->date));
}
void watch_list(mapping database) {
map(Array.sort_array(get_latest(database), compare_by_date),
print_episode);
}
string prompt_read(string prompt) {
write("%s: ", prompt);
return Stdio.stdin.gets();
}
array parse_date(string date) {
return (array(int))(date/".");
}
mapping prompt_for_episode() {
return make_episode(prompt_read("Series"),
prompt_read("Title"),
prompt_read("Episode"),
parse_date(prompt_read("Date watched")));
}
// pike offers encode_value() and decode_value() as standard ways // to save and read data, but that is not a human readable format. // therefore we are instead printing the structure as debug-output // which is a readable form as long as it only contains integers, // strings, mappings, arrays and multisets this format can be read by pike. // to read it we are creating a class that contains the data as a value, // which is then compiled and instantiated to allow us to pull the data out. void save_db(string filename, mapping database) {
Stdio.write_file(filename, sprintf("%O", database));
}
void watch_save() {
save_db("pwatch", db);
}
mapping load_db(string filename) {
if (file_stat(filename))
return compile_string("mixed data = " +
Stdio.read_file(filename) + ";")()->data;
else return ([]);
}
mapping get_series(string name, mapping database) {
return database[name];
}
array get_episode_list(string series, mapping database) {
return database[series]->episodes;
}
void watch_new_series(string name, string status, mapping database) {
database[name] = (["series":name, "status":status, "episodes":({}) ]);
}
mapping get_or_add_series(string name, mapping database) {
if (!database[name])
{
string answer = prompt_read("Add new series? [y/n]: ");
if (answer == "y")
watch_new_series(name, "active", database);
}
return database[name];
}
void watch_add(mapping database) {
mapping episode = prompt_for_episode();
string series_name = episode->series;
mapping series = get_or_add_series(series_name, database);
if (!series)
watch_add(database);
else
series->episodes = Array.unshift(series->episodes, episode);
}
void watch_load() {
db = load_db("pwatch");
}
int main(int argc, array argv) {
watch_load();
if (argc>1 && argv[1] == "add")
{
watch_add(db);
watch_save();
}
else
watch_list(db);
}</lang>
Ruby
<lang ruby>require 'date' require 'json' require 'securerandom'
class SimpleDatabase
def initialize(dbname, *fields)
@dbname = dbname
@filename = @dbname + ".dat"
@fields = fields
@maxl = @fields.collect {|f| f.length}.max
@data = {
'fields' => fields,
'items' => {},
'history' => [],
'tags' => {},
}
end
attr_reader :dbname, :fields
def self.open(dbname) db = new(dbname) db.read db end
def read()
if not File.exists?(@filename)
raise ArgumentError, "Database #@dbname has not been created"
end
@data = JSON.parse(File.read(@filename))
@fields = @data['fields']
@maxl = @fields.collect {|f| f.length}.max
end
def write()
File.open(@filename, 'w') {|f| f.write(JSON.generate(@data))}
end
def add(*values) id = SecureRandom.uuid @data['items'][id] = Hash[ @fields.zip(values) ] @data['history'] << [Time.now.to_f, id] id end
def tag(id, *tags)
tags.each do |tag|
if @data['tags'][tag].nil?
@data['tags'][tag] = [id]
else
@data['tags'][tag] << id
end
end
id
end
def latest
@data['history'].sort_by {|val| val[0]}.last.last
end
def get_item(id) @data['items'][id] end
def tags() @data['tags'].keys.sort end
def ids_for_tag(tag) @data['tags'][tag] end
def tags_for_id(id)
@data['tags'].keys.inject([]) do |tags, tag|
tags << tag if @data['tags'][tag].include?(id)
tags
end
end
def display(id)
item = get_item(id)
fmt = "%#{@maxl}s - %s\n"
puts fmt % ['id', id]
@fields.each {|f| print fmt % [f, item[f]]}
puts fmt % ['tags', tags_for_id(id).join(',')]
added = @data['history'].find {|x| x[1] == id}.first
puts fmt % ['date added', Time.at(added).ctime]
puts ""
end
def each()
@data['history'].each {|time, id| yield id}
end
def each_item_with_tag(tag)
@data['tags'][tag].each {|id| yield id}
end
end def usage()
puts <<END
usage: #{$0} command args ...
commands:
help create dbname field ... fields dbname add dbname value ... tag dbname id tag ... tags dbname list dbname [tag ...] latest dbname latest_by_tag dbname
END end
def open_database(args)
dbname = args.shift begin SimpleDatabase.open(dbname) rescue ArgumentError => e STDERR.puts e.message exit 1 end
end
def process_command_line(command, *args)
case command when 'help' usage
when 'create'
db = SimpleDatabase.new(*args)
db.write
puts "Database #{args[0]} created"
when 'fields'
db = open_database(args)
puts "Database #{db.dbname} fields:"
puts db.fields.join(',')
when 'add'
db = open_database(args)
id = db.add(*args)
db.write
puts "Database #{db.dbname} added id #{id}"
when 'tag'
db = open_database(args)
id = args.shift
db.tag(id, *args)
db.write
db.display(id)
when 'tags'
db = open_database(args)
puts "Database #{db.dbname} tags:"
puts db.tags.join(',')
when 'list'
db = open_database(args)
if args.empty?
db.each {|id| db.display(id)}
else
args.each do |tag|
puts "Items tagged #{tag}"
db.each_item_with_tag(tag) {|id| db.display(id)}
end
end
when 'latest' db = open_database(args) db.display(db.latest)
when 'latest_by_tag'
db = open_database(args)
db.tags.each do |tag|
puts tag
db.display(db.ids_for_tag(tag).last)
end
else
puts "Error: unknown command '#{command}'"
usage
end
end
process_command_line *ARGV</lang>
Sample session
$ ruby simple_database.rb create appointments event_title start_time stop_time location event_description
Database appointments created
$ ruby simple_database.rb add appointments "Wife's Birthday" "2011-11-01" "2011-11-01" "" "happy 39th"
Database appointments added id 6dd02195-1efe-40d1-b43e-c2efd852cd1d
$ ruby simple_database.rb tag appointments 6dd02195-1efe-40d1-b43e-c2efd852cd1d birthday family
id - 6dd02195-1efe-40d1-b43e-c2efd852cd1d
event_title - Wife's Birthday
start_time - 2011-11-01
stop_time - 2011-11-01
location -
event_description - happy 39th
tags - birthday,family
date added - Thu Nov 3 15:52:31 2011
$ ruby simple_database.rb add appointments "Parent-Teacher Conference" "2011-11-03 19:30" "2011-11-03 20:00" "school" "desc"
Database appointments added id 0190b835-401d-42da-9ed3-1d335d27b83c
$ ruby simple_database.rb tag appointments 0190b835-401d-42da-9ed3-1d335d27b83c school family
id - 0190b835-401d-42da-9ed3-1d335d27b83c
event_title - Parent-Teacher Conference
start_time - 2011-11-03 19:30
stop_time - 2011-11-03 20:00
location - school
event_description - desc
tags - family,school
date added - Thu Nov 3 15:54:05 2011
$ ruby simple_database.rb add appointments "Buy gift for wife" "2011-10-31 16:00" "2011-10-31 16:30" "the mall" "hmm, maybe jewelery?"
Database appointments added id 4023e6f1-bcc1-49e5-a59f-138157b413f4
$ ruby simple_database.rb tag appointments 4023e6f1-bcc1-49e5-a59f-138157b413f4 family last-minute
id - 4023e6f1-bcc1-49e5-a59f-138157b413f4
event_title - Buy gift for wife
start_time - 2011-10-31 16:00
stop_time - 2011-10-31 16:30
location - the mall
event_description - hmm, maybe jewelery?
tags - family,last-minute
date added - Thu Nov 3 15:55:02 2011
$ ruby simple_database.rb fields appointments
Database appointments fields:
event_title,start_time,stop_time,location,event_description
$ ruby simple_database.rb tags appointments
Database appointments tags:
birthday,family,last-minute,school
$ ruby simple_database.rb list appointments
id - 6dd02195-1efe-40d1-b43e-c2efd852cd1d
event_title - Wife's Birthday
start_time - 2011-11-01
stop_time - 2011-11-01
location -
event_description - happy 39th
tags - birthday,family
date added - Thu Nov 3 15:52:31 2011
id - 0190b835-401d-42da-9ed3-1d335d27b83c
event_title - Parent-Teacher Conference
start_time - 2011-11-03 19:30
stop_time - 2011-11-03 20:00
location - school
event_description - desc
tags - family,school
date added - Thu Nov 3 15:54:05 2011
id - 4023e6f1-bcc1-49e5-a59f-138157b413f4
event_title - Buy gift for wife
start_time - 2011-10-31 16:00
stop_time - 2011-10-31 16:30
location - the mall
event_description - hmm, maybe jewelery?
tags - family,last-minute
date added - Thu Nov 3 15:55:02 2011
$ cat appointments.dat
{"fields":["event_title","start_time","stop_time","location","event_description"],"items":{"6dd02195-1efe-40d1-b43e-c2efd852cd1d":{"event_title":"Wife's Birthday","start_time":"2011-11-01","stop_time":"2011-11-01","location":"","event_description":"happy 39th"},"0190b835-401d-42da-9ed3-1d335d27b83c":{"event_title":"Parent-Teacher Conference","start_time":"2011-11-03 19:30","stop_time":"2011-11-03 20:00","location":"school","event_description":"desc"},"4023e6f1-bcc1-49e5-a59f-138157b413f4":{"event_title":"Buy gift for wife","start_time":"2011-10-31 16:00","stop_time":"2011-10-31 16:30","location":"the mall","event_description":"hmm, maybe jewelery?"}},"history":[[1320349951.000625,"6dd02195-1efe-40d1-b43e-c2efd852cd1d"],[1320350045.4736252,"0190b835-401d-42da-9ed3-1d335d27b83c"],[1320350102.9486248,"4023e6f1-bcc1-49e5-a59f-138157b413f4"]],"tags":{"birthday":["6dd02195-1efe-40d1-b43e-c2efd852cd1d"],"family":["6dd02195-1efe-40d1-b43e-c2efd852cd1d","0190b835-401d-42da-9ed3-1d335d27b83c","4023e6f1-bcc1-49e5-a59f-138157b413f4"],"school":["0190b835-401d-42da-9ed3-1d335d27b83c"],"last-minute":["4023e6f1-bcc1-49e5-a59f-138157b413f4"]}}
Tcl
The format used is that of a Tcl dictionary, where each entry uses the title as a key and the remaining information (category, date and miscellaneous metadata) is the value associated with it. The only variation from the standard internal format is that entries are separated by newlines instead of spaces; this is still a legal value, but is a non-canonical. <lang tcl>#!/usr/bin/env tclsh8.6 package require Tcl 8.6 namespace eval udb {
variable db {}
proc Load {filename} {
variable db if {[catch {set f [open $filename]}]} { set db {} return } set db [read $f] close $f
}
proc Store {filename} {
variable db if {[catch {set f [open $filename w]}]} return dict for {nm inf} $db { puts $f [list $nm $inf] } close $f
}
proc add {title category {date "now"} args} {
variable db if {$date eq "now"} { set date [clock seconds] } else { set date [clock scan $date] } dict set db $title [list $category $date $args] return
}
proc Rec {nm cat date xtra} {
dict create description $nm category $cat date [clock format $date] \ {*}$xtra _names [dict keys $xtra]
} proc latest Template:Category "" {
variable db if {$category eq ""} { set d [lsort -stride 2 -index {1 1} -integer -decreasing $db] dict for {nm inf} $d break return [list [Rec $nm {*}$inf]] } set latestbycat {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { dict set latestbycat [lindex $inf 0] [list $nm {*}$inf] } return [list [Rec {*}[dict get $latestbycat $category]]]
}
proc latestpercategory {} {
variable db set latestbycat {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { dict set latestbycat [lindex $inf 0] [list $nm {*}$inf] } set result {} dict for {- inf} $latestbycat { lappend result [Rec {*}$inf] } return $result
}
proc bydate {} {
variable db set result {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { lappend result [Rec $nm {*}$inf] } return $result
}
namespace export add latest latestpercategory bydate namespace ensemble create
}
if {$argc < 2} {
puts stderr "wrong # args: should be \"$argv0 dbfile subcommand ?args...?\"" exit 1
} udb::Load [lindex $argv 0] set separator "" if {[catch {udb {*}[lrange $argv 1 end]} msg]} {
puts stderr [regsub "\"udb " $msg "\"$argv0 dbfile "] exit 1
} foreach row $msg {
puts -nonewline $separator
apply {row {
dict with row { puts "Title: $description" puts "Category: $category" puts "Date: $date" foreach v $_names { puts "${v}: [dict get $row $v]" } }
}} $row set separator [string repeat - 70]\n
}
udb::Store [lindex $argv 0]</lang> Sample session: <lang bash>bash$ udb.tcl db wrong # args: should be "udb.tcl dbfile subcommand ?args...?" bash$ udb.tcl db ? unknown or ambiguous subcommand "?": must be add, bydate, latest, or latestpercategory bash$ udb.tcl db add wrong # args: should be "udb.tcl dbfile add title category ?date? ?arg ...?" bash$ udb.tcl db add "Title 1" foo bash$ udb.tcl db add "Title 2" foo bash$ udb.tcl db add "Title 3" bar bash$ udb.tcl db bydate Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latest Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latest foo Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011 bash$ udb.tcl db latest bar Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latestpercategory Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db add "Title 4" bar "12:00 Monday last week" bash$ udb.tcl db bydate Title: Title 4 Category: bar Date: Mon Nov 14 12:00:00 GMT 2011
Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ cat db {Title 1} {foo 1321380718 {}} {Title 2} {foo 1321380721 {}} {Title 3} {bar 1321380727 {}} {Title 4} {bar 1321272000 {}} bash$ udb.tcl db add "Title 5" foo "12:00 Monday last week" Comment 'Wholly excellent!' bash$ cat db {Title 1} {foo 1321380718 {}} {Title 2} {foo 1321380721 {}} {Title 3} {bar 1321380727 {}} {Title 4} {bar 1321272000 {}} {Title 5} {foo 1321272000 {Comment {Wholly excellent!}}} bash$ udb.tcl db bydate Title: Title 4 Category: bar Date: Mon Nov 14 12:00:00 GMT 2011
Title: Title 5 Category: foo Date: Mon Nov 14 12:00:00 GMT 2011 Comment: Wholly excellent!
Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011</lang>
UNIX Shell
This format is guaranteed to be human readable: if you can type it, you can read it. <lang bash>#!/bin/sh
db_create() { mkdir ./"$1" && mkdir "./$1/.tag" && echo "Create DB \`$1'" }
db_delete() { rm -r ./"$1" && echo "Delete DB \`$1'" }
db_show() { if [ -z "$2" ]; then show_help; fi for x in "./$1/$2/"*; do echo "$x:" | sed "s/.*\///" cat "$x" | sed "s/^/ /" echo done
printf "Tags: " ls "./$1/$2/.tag" }
db_tag() { local db="$1" item="$2" shift shift for tag in $@; do mkdir "./$db/.tag/$tag" ln -s "$PWD/$db/$item" "./$db/.tag/$tag/" touch "./$db/$item/.tag/$tag" done }
show_help() { echo "Usage: $0 command [args]" echo "Commands:" cat $0 | grep ") ##" | grep -v grep | sed 's/) ## /:\t/' exit }
if [ -z "$1" ]; then show_help; fi
action=$1 it=database shift case $action in create) ## db -- create $it db_create "$@" ;;
drop) ## db -- delete $it db_delete "$@" ;;
add) ## db item -- add new item to $it mkdir -p "./$1/$2/.tag" && touch "./$1/$2/Description" ;;
rem) ## db item -- delete item from $it rm -r "./$1/$2" rm "./$1/.tag/"*"/$2" ;;
show) ## db item -- show item db_show "$@" ;;
newtag) ## db new-tag-name -- create new tag name mkdir "./$1/.tag/$2" ;;
prop) ## db item property-name property-content -- add property to item echo "$4" > "./$1/$2/$3" ;;
tag) ## db item tag [more-tags...] -- mark item with tags db_tag "$@" ;;
last) ## db -- show latest item ls "$1" --sort=time | tail -n 1 ;;
list) ## db -- list all items ls "$1" -1 --sort=time ;;
last-all) ## db -- list items in each category for x in "$1/.tag/"*; do echo "$x" | sed 's/.*\//Tag: /' printf " " ls "$x" --sort=time | tail -n 1 echo done ;;
help) ## this message show_help ;;
*) echo Bad DB command: $1 show_help ;; esac</lang> Sample usage (assuming script is named "sdb"):<lang>$ sdb create CDs Create DB `CDs' $ sdb add CDs Bookends $ sdb prop CDs Bookends artists "Simon & Garfunkel" $ sdb add CDs "Ode to joy" $ sdb prop CDs "Ode to joy" artist "Beethoven" $ sdb tag CDs Bookends rock folk # I'm not sure about this $ sdb tag CDs "Ode to joy" classical $ sdb show CDs Bookends Description:
artists:
Simon & Garfunkel
Tags: folk rock $ sdb prop CDs "Ode to joy" Description "Sym. No. 9" $ sdb show CDs "Ode to joy" Description:
Sym. No. 9
artist:
Beethoven
Tags: classical $ sdb last-all CDs Tag: classical
Ode to joy
Tag: folk
Bookends
Tag: rock
Bookends
$ sdb drop CDs Delete DB `CDs' $</lang>