hgbook
view es/tour-basic.tex @ 352:9f460a706292
translated a few sections from tour-basic.tex
| author | jerojasro@localhost |
|---|---|
| date | Mon Oct 20 00:19:24 2008 -0500 (2008-10-20) |
| parents | 2fb78d342e07 |
| children | 5e325122bea5 |
line source
1 \chapter{Una gira de Mercurial: lo básico}
2 \label{chap:tour-basic}
4 \section{Instalar Mercurial en su sistema}
5 \label{sec:tour:install}
6 Hay paquetes binarios precompilados de Mercurial disponibles para cada
7 sistema operativo popular. Esto hace fácil empezar a usar Mercurial
8 en su computador inmediatamente.
10 \subsection{Linux}
12 Dado que cada distribución de Linux tiene sus propias herramientas de
13 manejo de paquetes, políticas, y ritmos de desarrollo, es difícil dar
14 un conjunto exhaustivo de instrucciones sobre cómo instalar el paquete
15 de Mercurial. La versión de Mercurial que usted tenga a disposición
16 puede variar dependiendo de qué tan activa sea la persona que mantiene
17 el paquete para su distribución.
19 Para mantener las cosas simples, me enfocaré en instalar Mercurial
20 desde la línea de comandos en las distribuciones de Linux más
21 populares. La mayoría de estas distribuciones proveen administradores
22 de paquetes gráficos que le permitirán instalar Mercurial con un solo
23 clic; el nombre de paquete a buscar es \texttt{mercurial}.
25 \begin{itemize}
26 \item[Debian]
27 \begin{codesample4}
28 apt-get install mercurial
29 \end{codesample4}
31 \item[Fedora Core]
32 \begin{codesample4}
33 yum install mercurial
34 \end{codesample4}
36 \item[Gentoo]
37 \begin{codesample4}
38 emerge mercurial
39 \end{codesample4}
41 \item[OpenSUSE]
42 \begin{codesample4}
43 yum install mercurial
44 \end{codesample4}
46 \item[Ubuntu] El paquete de Mercurial de Ubuntu está basado en el de
47 Debian. Para instalarlo, ejecute el siguiente comando.
48 \begin{codesample4}
49 apt-get install mercurial
50 \end{codesample4}
51 El paquete de Mercurial para Ubuntu tiende a atrasarse con respecto
52 a la versión de Debian por un margen de tiempo considerable
53 (al momento de escribir esto, 7 meses), lo que en algunos casos
54 significará que usted puede encontrarse con problemas que ya habrán
55 sido resueltos en el paquete de Debian.
56 \end{itemize}
58 \subsection{Solaris}
60 SunFreeWare, en \url{http://www.sunfreeware.com}, es una buena fuente
61 para un gran número de paquetes compilados para Solaris para las
62 arquitecturas Intel y Sparc de 32 y 64 bits, incluyendo versiones
63 actuales de Mercurial.
65 \subsection{Mac OS X}
67 Lee Cantey publica un instalador de Mercurial para Mac OS~X en
68 \url{http://mercurial.berkwood.com}. Este paquete funciona en tanto
69 en Macs basados en Intel como basados en PowerPC. Antes de que pueda
70 usarlo, usted debe instalar una versión compatible de Universal
71 MacPython~\cite{web:macpython}. Esto es fácil de hacer; simplemente
72 siga las instrucciones de el sitio de Lee.
74 También es posible instalar Mercurial usando Fink o MacPorts, dos
75 administradores de paquetes gratuitos y populares para Mac OS X. Si
76 usted tiene Fink, use \command{sudo apt-get install mercurial-py25}.
77 Si usa MacPorts, \command{sudo port install mercurial}.
79 \subsection{Windows}
81 Lee Cantey publica un instalador de Mercurial para Windows en
82 \url{http://mercurial.berkwood.com}. Este paquete no tiene
83 % TODO traducción de it just works. Agreed?
84 dependencias externas; ``simplemente funciona''.
86 \begin{note}
87 La versión de Windows de Mercurial no convierte automáticamente
88 los fines de línea entre estilos Windows y Unix. Si usted desea
89 compartir trabajo con usuarios de Unix, deberá hacer un trabajo
90 adicional de configuración. XXX Terminar esto.
91 \end{note}
93 \section{Arrancando}
95 Para empezar, usaremos el comando \hgcmd{version} para revisar si
96 Mercurial está instalado adecuadamente. La información de la versión
97 que es impresa no es tan importante; lo que nos importa es si imprime
98 algo en absoluto.
100 \interaction{tour.version}
102 % TODO builtin-> integrado?
103 \subsection{Ayuda integrada}
105 Mercurial provee un sistema de ayuda integrada. Esto es invaluable
106 para ésas ocasiones en la que usted está atorado tratando de recordar
107 cómo ejecutar un comando. Si está completamente atorado, simplemente
108 ejecute \hgcmd{help}; esto imprimirá una breve lista de comandos,
109 junto con una descripción de qué hace cada uno. Si usted solicita
110 ayuda sobre un comando específico (como abajo), se imprime información
111 más detallada.
112 \interaction{tour.help}
113 Para un nivel más impresionante de detalle (que usted no va a
114 necesitar usualmente) ejecute \hgcmdargs{help}{\hggopt{-v}}. La opción
115 \hggopt{-v} es la abreviación para \hggopt{--verbose}, y le indica a
116 Mercurial que imprima más información de lo que haría usualmente.
118 \section{Trabajar con un repositorio}
120 En Mercurial, todo sucede dentro de un \emph{repositorio}. El
121 repositorio para un proyecto contiene todos los archivos que
122 ``pertenecen a'' ése proyecto, junto con un registro histórico de los
123 archivos de ese proyecto.
125 No hay nada particularmente mágico acerca de un repositorio; es
126 simplemente un árbol de directorios en su sistema de archivos que
127 Mercurial trata como especial. Usted puede renombrar o borrar un
128 repositorio en el momento que lo desee, usando bien sea la línea de
129 comandos o su explorador de ficheros.
131 \subsection{Hacer una copia local de un repositorio}
133 \emph{Copiar} un repositorio es sólo ligeramente especial. Aunque
134 usted podría usar un programa normal de copia de archivos para hacer
135 una copia del repositorio, es mejor usar el comando integrado que
136 Mercurial ofrece. Este comando se llama \hgcmd{clone}\ndt{Del término
137 ``clonar'' en inglés.}, porque crea una copia idéntica de un
138 repositorio existente.
139 \interaction{tour.clone}
140 Si nuestro clonado tiene éxito, deberíamos tener un directorio local
141 llamado \dirname{hello}. Este directorio contendrá algunos archivos.
142 \interaction{tour.ls}
143 Estos archivos tienen el mismo contenido e historial en nuestro
144 repositorio y en el repositorio que clonamos.
146 Cada repositorio Mercurial está completo, es autocontenido e
147 independiente. Contiene su propia copia de los archivos y la historia
148 de un proyecto. Un repositorio clonado recuerda la ubicación de la que
149 fue clonado, pero no se comunica con ese repositorio, ni con ningún
150 otro, a menos que usted le indique que lo haga.
152 Lo que esto significa por ahora es que somos libres de experimentar
153 con nuestro repositorio, con la tranquilidad de saber que es
154 % TODO finish paragraph, figure out what to say instead of sandbox
156 What this means for now is that we're free to experiment with our
157 repository, safe in the knowledge that it's a private ``sandbox'' that
158 won't affect anyone else.
160 \subsection{What's in a repository?}
162 When we take a more detailed look inside a repository, we can see that
163 it contains a directory named \dirname{.hg}. This is where Mercurial
164 keeps all of its metadata for the repository.
165 \interaction{tour.ls-a}
167 The contents of the \dirname{.hg} directory and its subdirectories are
168 private to Mercurial. Every other file and directory in the
169 repository is yours to do with as you please.
171 To introduce a little terminology, the \dirname{.hg} directory is the
172 ``real'' repository, and all of the files and directories that coexist
173 with it are said to live in the \emph{working directory}. An easy way
174 to remember the distinction is that the \emph{repository} contains the
175 \emph{history} of your project, while the \emph{working directory}
176 contains a \emph{snapshot} of your project at a particular point in
177 history.
179 \section{A tour through history}
181 One of the first things we might want to do with a new, unfamiliar
182 repository is understand its history. The \hgcmd{log} command gives
183 us a view of history.
184 \interaction{tour.log}
185 By default, this command prints a brief paragraph of output for each
186 change to the project that was recorded. In Mercurial terminology, we
187 call each of these recorded events a \emph{changeset}, because it can
188 contain a record of changes to several files.
190 The fields in a record of output from \hgcmd{log} are as follows.
191 \begin{itemize}
192 \item[\texttt{changeset}] This field has the format of a number,
193 followed by a colon, followed by a hexadecimal string. These are
194 \emph{identifiers} for the changeset. There are two identifiers
195 because the number is shorter and easier to type than the hex
196 string.
197 \item[\texttt{user}] The identity of the person who created the
198 changeset. This is a free-form field, but it most often contains a
199 person's name and email address.
200 \item[\texttt{date}] The date and time on which the changeset was
201 created, and the timezone in which it was created. (The date and
202 time are local to that timezone; they display what time and date it
203 was for the person who created the changeset.)
204 \item[\texttt{summary}] The first line of the text message that the
205 creator of the changeset entered to describe the changeset.
206 \end{itemize}
207 The default output printed by \hgcmd{log} is purely a summary; it is
208 missing a lot of detail.
210 Figure~\ref{fig:tour-basic:history} provides a graphical representation of
211 the history of the \dirname{hello} repository, to make it a little
212 easier to see which direction history is ``flowing'' in. We'll be
213 returning to this figure several times in this chapter and the chapter
214 that follows.
216 \begin{figure}[ht]
217 \centering
218 \grafix{tour-history}
219 \caption{Graphical history of the \dirname{hello} repository}
220 \label{fig:tour-basic:history}
221 \end{figure}
223 \subsection{Changesets, revisions, and talking to other
224 people}
226 As English is a notoriously sloppy language, and computer science has
227 a hallowed history of terminological confusion (why use one term when
228 four will do?), revision control has a variety of words and phrases
229 that mean the same thing. If you are talking about Mercurial history
230 with other people, you will find that the word ``changeset'' is often
231 compressed to ``change'' or (when written) ``cset'', and sometimes a
232 changeset is referred to as a ``revision'' or a ``rev''.
234 While it doesn't matter what \emph{word} you use to refer to the
235 concept of ``a~changeset'', the \emph{identifier} that you use to
236 refer to ``a~\emph{specific} changeset'' is of great importance.
237 Recall that the \texttt{changeset} field in the output from
238 \hgcmd{log} identifies a changeset using both a number and a
239 hexadecimal string.
240 \begin{itemize}
241 \item The revision number is \emph{only valid in that repository},
242 \item while the hex string is the \emph{permanent, unchanging
243 identifier} that will always identify that exact changeset in
244 \emph{every} copy of the repository.
245 \end{itemize}
246 This distinction is important. If you send someone an email talking
247 about ``revision~33'', there's a high likelihood that their
248 revision~33 will \emph{not be the same} as yours. The reason for this
249 is that a revision number depends on the order in which changes
250 arrived in a repository, and there is no guarantee that the same
251 changes will happen in the same order in different repositories.
252 Three changes $a,b,c$ can easily appear in one repository as $0,1,2$,
253 while in another as $1,0,2$.
255 Mercurial uses revision numbers purely as a convenient shorthand. If
256 you need to discuss a changeset with someone, or make a record of a
257 changeset for some other reason (for example, in a bug report), use
258 the hexadecimal identifier.
260 \subsection{Viewing specific revisions}
262 To narrow the output of \hgcmd{log} down to a single revision, use the
263 \hgopt{log}{-r} (or \hgopt{log}{--rev}) option. You can use either a
264 revision number or a long-form changeset identifier, and you can
265 provide as many revisions as you want. \interaction{tour.log-r}
267 If you want to see the history of several revisions without having to
268 list each one, you can use \emph{range notation}; this lets you
269 express the idea ``I want all revisions between $a$ and $b$,
270 inclusive''.
271 \interaction{tour.log.range}
272 Mercurial also honours the order in which you specify revisions, so
273 \hgcmdargs{log}{-r 2:4} prints $2,3,4$ while \hgcmdargs{log}{-r 4:2}
274 prints $4,3,2$.
276 \subsection{More detailed information}
278 While the summary information printed by \hgcmd{log} is useful if you
279 already know what you're looking for, you may need to see a complete
280 description of the change, or a list of the files changed, if you're
281 trying to decide whether a changeset is the one you're looking for.
282 The \hgcmd{log} command's \hggopt{-v} (or \hggopt{--verbose})
283 option gives you this extra detail.
284 \interaction{tour.log-v}
286 If you want to see both the description and content of a change, add
287 the \hgopt{log}{-p} (or \hgopt{log}{--patch}) option. This displays
288 the content of a change as a \emph{unified diff} (if you've never seen
289 a unified diff before, see section~\ref{sec:mq:patch} for an overview).
290 \interaction{tour.log-vp}
292 \section{All about command options}
294 Let's take a brief break from exploring Mercurial commands to discuss
295 a pattern in the way that they work; you may find this useful to keep
296 in mind as we continue our tour.
298 Mercurial has a consistent and straightforward approach to dealing
299 with the options that you can pass to commands. It follows the
300 conventions for options that are common to modern Linux and Unix
301 systems.
302 \begin{itemize}
303 \item Every option has a long name. For example, as we've already
304 seen, the \hgcmd{log} command accepts a \hgopt{log}{--rev} option.
305 \item Most options have short names, too. Instead of
306 \hgopt{log}{--rev}, we can use \hgopt{log}{-r}. (The reason that
307 some options don't have short names is that the options in question
308 are rarely used.)
309 \item Long options start with two dashes (e.g.~\hgopt{log}{--rev}),
310 while short options start with one (e.g.~\hgopt{log}{-r}).
311 \item Option naming and usage is consistent across commands. For
312 example, every command that lets you specify a changeset~ID or
313 revision number accepts both \hgopt{log}{-r} and \hgopt{log}{--rev}
314 arguments.
315 \end{itemize}
316 In the examples throughout this book, I use short options instead of
317 long. This just reflects my own preference, so don't read anything
318 significant into it.
320 Most commands that print output of some kind will print more output
321 when passed a \hggopt{-v} (or \hggopt{--verbose}) option, and less
322 when passed \hggopt{-q} (or \hggopt{--quiet}).
324 \section{Making and reviewing changes}
326 Now that we have a grasp of viewing history in Mercurial, let's take a
327 look at making some changes and examining them.
329 The first thing we'll do is isolate our experiment in a repository of
330 its own. We use the \hgcmd{clone} command, but we don't need to
331 clone a copy of the remote repository. Since we already have a copy
332 of it locally, we can just clone that instead. This is much faster
333 than cloning over the network, and cloning a local repository uses
334 less disk space in most cases, too.
335 \interaction{tour.reclone}
336 As an aside, it's often good practice to keep a ``pristine'' copy of a
337 remote repository around, which you can then make temporary clones of
338 to create sandboxes for each task you want to work on. This lets you
339 work on multiple tasks in parallel, each isolated from the others
340 until it's complete and you're ready to integrate it back. Because
341 local clones are so cheap, there's almost no overhead to cloning and
342 destroying repositories whenever you want.
344 In our \dirname{my-hello} repository, we have a file
345 \filename{hello.c} that contains the classic ``hello, world'' program.
346 Let's use the ancient and venerable \command{sed} command to edit this
347 file so that it prints a second line of output. (I'm only using
348 \command{sed} to do this because it's easy to write a scripted example
349 this way. Since you're not under the same constraint, you probably
350 won't want to use \command{sed}; simply use your preferred text editor to
351 do the same thing.)
352 \interaction{tour.sed}
354 Mercurial's \hgcmd{status} command will tell us what Mercurial knows
355 about the files in the repository.
356 \interaction{tour.status}
357 The \hgcmd{status} command prints no output for some files, but a line
358 starting with ``\texttt{M}'' for \filename{hello.c}. Unless you tell
359 it to, \hgcmd{status} will not print any output for files that have
360 not been modified.
362 The ``\texttt{M}'' indicates that Mercurial has noticed that we
363 modified \filename{hello.c}. We didn't need to \emph{inform}
364 Mercurial that we were going to modify the file before we started, or
365 that we had modified the file after we were done; it was able to
366 figure this out itself.
368 It's a little bit helpful to know that we've modified
369 \filename{hello.c}, but we might prefer to know exactly \emph{what}
370 changes we've made to it. To do this, we use the \hgcmd{diff}
371 command.
372 \interaction{tour.diff}
374 \section{Recording changes in a new changeset}
376 We can modify files, build and test our changes, and use
377 \hgcmd{status} and \hgcmd{diff} to review our changes, until we're
378 satisfied with what we've done and arrive at a natural stopping point
379 where we want to record our work in a new changeset.
381 The \hgcmd{commit} command lets us create a new changeset; we'll
382 usually refer to this as ``making a commit'' or ``committing''.
384 \subsection{Setting up a username}
386 When you try to run \hgcmd{commit} for the first time, it is not
387 guaranteed to succeed. Mercurial records your name and address with
388 each change that you commit, so that you and others will later be able
389 to tell who made each change. Mercurial tries to automatically figure
390 out a sensible username to commit the change with. It will attempt
391 each of the following methods, in order:
392 \begin{enumerate}
393 \item If you specify a \hgopt{commit}{-u} option to the \hgcmd{commit}
394 command on the command line, followed by a username, this is always
395 given the highest precedence.
396 \item If you have set the \envar{HGUSER} environment variable, this is
397 checked next.
398 \item If you create a file in your home directory called
399 \sfilename{.hgrc}, with a \rcitem{ui}{username} entry, that will be
400 used next. To see what the contents of this file should look like,
401 refer to section~\ref{sec:tour-basic:username} below.
402 \item If you have set the \envar{EMAIL} environment variable, this
403 will be used next.
404 \item Mercurial will query your system to find out your local user
405 name and host name, and construct a username from these components.
406 Since this often results in a username that is not very useful, it
407 will print a warning if it has to do this.
408 \end{enumerate}
409 If all of these mechanisms fail, Mercurial will fail, printing an
410 error message. In this case, it will not let you commit until you set
411 up a username.
413 You should think of the \envar{HGUSER} environment variable and the
414 \hgopt{commit}{-u} option to the \hgcmd{commit} command as ways to
415 \emph{override} Mercurial's default selection of username. For normal
416 use, the simplest and most robust way to set a username for yourself
417 is by creating a \sfilename{.hgrc} file; see below for details.
419 \subsubsection{Creating a Mercurial configuration file}
420 \label{sec:tour-basic:username}
422 To set a user name, use your favourite editor to create a file called
423 \sfilename{.hgrc} in your home directory. Mercurial will use this
424 file to look up your personalised configuration settings. The initial
425 contents of your \sfilename{.hgrc} should look like this.
426 \begin{codesample2}
427 # This is a Mercurial configuration file.
428 [ui]
429 username = Firstname Lastname <email.address@domain.net>
430 \end{codesample2}
431 The ``\texttt{[ui]}'' line begins a \emph{section} of the config file,
432 so you can read the ``\texttt{username = ...}'' line as meaning ``set
433 the value of the \texttt{username} item in the \texttt{ui} section''.
434 A section continues until a new section begins, or the end of the
435 file. Mercurial ignores empty lines and treats any text from
436 ``\texttt{\#}'' to the end of a line as a comment.
438 \subsubsection{Choosing a user name}
440 You can use any text you like as the value of the \texttt{username}
441 config item, since this information is for reading by other people,
442 but for interpreting by Mercurial. The convention that most people
443 follow is to use their name and email address, as in the example
444 above.
446 \begin{note}
447 Mercurial's built-in web server obfuscates email addresses, to make
448 it more difficult for the email harvesting tools that spammers use.
449 This reduces the likelihood that you'll start receiving more junk
450 email if you publish a Mercurial repository on the web.
451 \end{note}
453 \subsection{Writing a commit message}
455 When we commit a change, Mercurial drops us into a text editor, to
456 enter a message that will describe the modifications we've made in
457 this changeset. This is called the \emph{commit message}. It will be
458 a record for readers of what we did and why, and it will be printed by
459 \hgcmd{log} after we've finished committing.
460 \interaction{tour.commit}
462 The editor that the \hgcmd{commit} command drops us into will contain
463 an empty line, followed by a number of lines starting with
464 ``\texttt{HG:}''.
465 \begin{codesample2}
466 \emph{empty line}
467 HG: changed hello.c
468 \end{codesample2}
469 Mercurial ignores the lines that start with ``\texttt{HG:}''; it uses
470 them only to tell us which files it's recording changes to. Modifying
471 or deleting these lines has no effect.
473 \subsection{Writing a good commit message}
475 Since \hgcmd{log} only prints the first line of a commit message by
476 default, it's best to write a commit message whose first line stands
477 alone. Here's a real example of a commit message that \emph{doesn't}
478 follow this guideline, and hence has a summary that is not readable.
479 \begin{codesample2}
480 changeset: 73:584af0e231be
481 user: Censored Person <censored.person@example.org>
482 date: Tue Sep 26 21:37:07 2006 -0700
483 summary: include buildmeister/commondefs. Add an exports and install
484 \end{codesample2}
486 As far as the remainder of the contents of the commit message are
487 concerned, there are no hard-and-fast rules. Mercurial itself doesn't
488 interpret or care about the contents of the commit message, though
489 your project may have policies that dictate a certain kind of
490 formatting.
492 My personal preference is for short, but informative, commit messages
493 that tell me something that I can't figure out with a quick glance at
494 the output of \hgcmdargs{log}{--patch}.
496 \subsection{Aborting a commit}
498 If you decide that you don't want to commit while in the middle of
499 editing a commit message, simply exit from your editor without saving
500 the file that it's editing. This will cause nothing to happen to
501 either the repository or the working directory.
503 If we run the \hgcmd{commit} command without any arguments, it records
504 all of the changes we've made, as reported by \hgcmd{status} and
505 \hgcmd{diff}.
507 \subsection{Admiring our new handiwork}
509 Once we've finished the commit, we can use the \hgcmd{tip} command to
510 display the changeset we just created. This command produces output
511 that is identical to \hgcmd{log}, but it only displays the newest
512 revision in the repository.
513 \interaction{tour.tip}
514 We refer to the newest revision in the repository as the tip revision,
515 or simply the tip.
517 \section{Sharing changes}
519 We mentioned earlier that repositories in Mercurial are
520 self-contained. This means that the changeset we just created exists
521 only in our \dirname{my-hello} repository. Let's look at a few ways
522 that we can propagate this change into other repositories.
524 \subsection{Pulling changes from another repository}
525 \label{sec:tour:pull}
527 To get started, let's clone our original \dirname{hello} repository,
528 which does not contain the change we just committed. We'll call our
529 temporary repository \dirname{hello-pull}.
530 \interaction{tour.clone-pull}
532 We'll use the \hgcmd{pull} command to bring changes from
533 \dirname{my-hello} into \dirname{hello-pull}. However, blindly
534 pulling unknown changes into a repository is a somewhat scary
535 prospect. Mercurial provides the \hgcmd{incoming} command to tell us
536 what changes the \hgcmd{pull} command \emph{would} pull into the
537 repository, without actually pulling the changes in.
538 \interaction{tour.incoming}
539 (Of course, someone could cause more changesets to appear in the
540 repository that we ran \hgcmd{incoming} in, before we get a chance to
541 \hgcmd{pull} the changes, so that we could end up pulling changes that we
542 didn't expect.)
544 Bringing changes into a repository is a simple matter of running the
545 \hgcmd{pull} command, and telling it which repository to pull from.
546 \interaction{tour.pull}
547 As you can see from the before-and-after output of \hgcmd{tip}, we
548 have successfully pulled changes into our repository. There remains
549 one step before we can see these changes in the working directory.
551 \subsection{Updating the working directory}
553 We have so far glossed over the relationship between a repository and
554 its working directory. The \hgcmd{pull} command that we ran in
555 section~\ref{sec:tour:pull} brought changes into the repository, but
556 if we check, there's no sign of those changes in the working
557 directory. This is because \hgcmd{pull} does not (by default) touch
558 the working directory. Instead, we use the \hgcmd{update} command to
559 do this.
560 \interaction{tour.update}
562 It might seem a bit strange that \hgcmd{pull} doesn't update the
563 working directory automatically. There's actually a good reason for
564 this: you can use \hgcmd{update} to update the working directory to
565 the state it was in at \emph{any revision} in the history of the
566 repository. If you had the working directory updated to an old
567 revision---to hunt down the origin of a bug, say---and ran a
568 \hgcmd{pull} which automatically updated the working directory to a
569 new revision, you might not be terribly happy.
571 However, since pull-then-update is such a common thing to do,
572 Mercurial lets you combine the two by passing the \hgopt{pull}{-u}
573 option to \hgcmd{pull}.
574 \begin{codesample2}
575 hg pull -u
576 \end{codesample2}
577 If you look back at the output of \hgcmd{pull} in
578 section~\ref{sec:tour:pull} when we ran it without \hgopt{pull}{-u},
579 you can see that it printed a helpful reminder that we'd have to take
580 an explicit step to update the working directory:
581 \begin{codesample2}
582 (run 'hg update' to get a working copy)
583 \end{codesample2}
585 To find out what revision the working directory is at, use the
586 \hgcmd{parents} command.
587 \interaction{tour.parents}
588 If you look back at figure~\ref{fig:tour-basic:history}, you'll see
589 arrows connecting each changeset. The node that the arrow leads
590 \emph{from} in each case is a parent, and the node that the arrow
591 leads \emph{to} is its child. The working directory has a parent in
592 just the same way; this is the changeset that the working directory
593 currently contains.
595 To update the working directory to a particular revision, give a
596 revision number or changeset~ID to the \hgcmd{update} command.
597 \interaction{tour.older}
598 If you omit an explicit revision, \hgcmd{update} will update to the
599 tip revision, as shown by the second call to \hgcmd{update} in the
600 example above.
602 \subsection{Pushing changes to another repository}
604 Mercurial lets us push changes to another repository, from the
605 repository we're currently visiting. As with the example of
606 \hgcmd{pull} above, we'll create a temporary repository to push our
607 changes into.
608 \interaction{tour.clone-push}
609 The \hgcmd{outgoing} command tells us what changes would be pushed
610 into another repository.
611 \interaction{tour.outgoing}
612 And the \hgcmd{push} command does the actual push.
613 \interaction{tour.push}
614 As with \hgcmd{pull}, the \hgcmd{push} command does not update the
615 working directory in the repository that it's pushing changes into.
616 (Unlike \hgcmd{pull}, \hgcmd{push} does not provide a \texttt{-u}
617 option that updates the other repository's working directory.)
619 What happens if we try to pull or push changes and the receiving
620 repository already has those changes? Nothing too exciting.
621 \interaction{tour.push.nothing}
623 \subsection{Sharing changes over a network}
625 The commands we have covered in the previous few sections are not
626 limited to working with local repositories. Each works in exactly the
627 same fashion over a network connection; simply pass in a URL instead
628 of a local path.
629 \interaction{tour.outgoing.net}
630 In this example, we can see what changes we could push to the remote
631 repository, but the repository is understandably not set up to let
632 anonymous users push to it.
633 \interaction{tour.push.net}
635 %%% Local Variables:
636 %%% mode: latex
637 %%% TeX-master: "00book"
638 %%% End: