hgbook

view es/tour-basic.tex @ 357:dae36f024e14

some paragraphs translated, added a couple of rules-of-thumb for translation of terms
author Javier Rojas <jerojasro@devnull.li>
date Thu Oct 23 03:13:35 2008 -0500 (2008-10-23)
parents 5e325122bea5
children 15a6b61335aa
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 una
154 % TODO figure out what to say instead of sandbox
155 ``caja de arena'' privada que no afectará a nadie más.
157 \subsection{Qué hay en un repositorio?}
159 Cuando miramos en detalle dentro de un repositorio, podemos ver que
160 contiene un directorio llamado \dirname{.hg}. Aquí es donde Mercurial
161 mantiene todos los metadatos del repositorio.
162 \interaction{tour.ls-a}
164 Los contenidos del directorio \dirname{.hg} y sus subdirectorios son
165 exclusivos de Mercurial. Usted es libre de hacer lo que desee con
166 cualquier otro archivo o directorio en el repositorio.
168 Para introducir algo de terminología, el directorio \dirname{.hg} es
169 el repositorio ``real'', y todos los archivos y directorios que
170 coexisten con él están en el \emph{directorio de trabajo}. Una forma
171 sencilla de recordar esta distinción es que el \emph{repositorio}
172 % TODO unificar con Igor, si historia o historial
173 contiene el \emph{historial} de su proyecto, mientras que el
174 \emph{directorio de trabajo} contiene una \emph{instantánea} de su
175 proyecto en un punto particular del historial.
177 \section{Vistazo rápido al historial}
179 Una de las primeras cosas que se desea hacer con un repositorio nuevo,
180 poco conocido, es conocer su historial. el comando \hgcmd{log} nos
181 permite ver el mismo.
182 \interaction{tour.log}
183 By default, this command prints a brief paragraph of output for each
184 change to the project that was recorded. In Mercurial terminology, we
185 call each of these recorded events a \emph{changeset}, because it can
186 contain a record of changes to several files.
188 The fields in a record of output from \hgcmd{log} are as follows.
189 \begin{itemize}
190 \item[\texttt{changeset}] This field has the format of a number,
191 followed by a colon, followed by a hexadecimal string. These are
192 \emph{identifiers} for the changeset. There are two identifiers
193 because the number is shorter and easier to type than the hex
194 string.
195 \item[\texttt{user}] The identity of the person who created the
196 changeset. This is a free-form field, but it most often contains a
197 person's name and email address.
198 \item[\texttt{date}] The date and time on which the changeset was
199 created, and the timezone in which it was created. (The date and
200 time are local to that timezone; they display what time and date it
201 was for the person who created the changeset.)
202 \item[\texttt{summary}] The first line of the text message that the
203 creator of the changeset entered to describe the changeset.
204 \end{itemize}
205 The default output printed by \hgcmd{log} is purely a summary; it is
206 missing a lot of detail.
208 Figure~\ref{fig:tour-basic:history} provides a graphical representation of
209 the history of the \dirname{hello} repository, to make it a little
210 easier to see which direction history is ``flowing'' in. We'll be
211 returning to this figure several times in this chapter and the chapter
212 that follows.
214 \begin{figure}[ht]
215 \centering
216 \grafix{tour-history}
217 \caption{Graphical history of the \dirname{hello} repository}
218 \label{fig:tour-basic:history}
219 \end{figure}
221 \subsection{Changesets, revisions, and talking to other
222 people}
224 As English is a notoriously sloppy language, and computer science has
225 a hallowed history of terminological confusion (why use one term when
226 four will do?), revision control has a variety of words and phrases
227 that mean the same thing. If you are talking about Mercurial history
228 with other people, you will find that the word ``changeset'' is often
229 compressed to ``change'' or (when written) ``cset'', and sometimes a
230 changeset is referred to as a ``revision'' or a ``rev''.
232 While it doesn't matter what \emph{word} you use to refer to the
233 concept of ``a~changeset'', the \emph{identifier} that you use to
234 refer to ``a~\emph{specific} changeset'' is of great importance.
235 Recall that the \texttt{changeset} field in the output from
236 \hgcmd{log} identifies a changeset using both a number and a
237 hexadecimal string.
238 \begin{itemize}
239 \item The revision number is \emph{only valid in that repository},
240 \item while the hex string is the \emph{permanent, unchanging
241 identifier} that will always identify that exact changeset in
242 \emph{every} copy of the repository.
243 \end{itemize}
244 This distinction is important. If you send someone an email talking
245 about ``revision~33'', there's a high likelihood that their
246 revision~33 will \emph{not be the same} as yours. The reason for this
247 is that a revision number depends on the order in which changes
248 arrived in a repository, and there is no guarantee that the same
249 changes will happen in the same order in different repositories.
250 Three changes $a,b,c$ can easily appear in one repository as $0,1,2$,
251 while in another as $1,0,2$.
253 Mercurial uses revision numbers purely as a convenient shorthand. If
254 you need to discuss a changeset with someone, or make a record of a
255 changeset for some other reason (for example, in a bug report), use
256 the hexadecimal identifier.
258 \subsection{Viewing specific revisions}
260 To narrow the output of \hgcmd{log} down to a single revision, use the
261 \hgopt{log}{-r} (or \hgopt{log}{--rev}) option. You can use either a
262 revision number or a long-form changeset identifier, and you can
263 provide as many revisions as you want. \interaction{tour.log-r}
265 If you want to see the history of several revisions without having to
266 list each one, you can use \emph{range notation}; this lets you
267 express the idea ``I want all revisions between $a$ and $b$,
268 inclusive''.
269 \interaction{tour.log.range}
270 Mercurial also honours the order in which you specify revisions, so
271 \hgcmdargs{log}{-r 2:4} prints $2,3,4$ while \hgcmdargs{log}{-r 4:2}
272 prints $4,3,2$.
274 \subsection{More detailed information}
276 While the summary information printed by \hgcmd{log} is useful if you
277 already know what you're looking for, you may need to see a complete
278 description of the change, or a list of the files changed, if you're
279 trying to decide whether a changeset is the one you're looking for.
280 The \hgcmd{log} command's \hggopt{-v} (or \hggopt{--verbose})
281 option gives you this extra detail.
282 \interaction{tour.log-v}
284 If you want to see both the description and content of a change, add
285 the \hgopt{log}{-p} (or \hgopt{log}{--patch}) option. This displays
286 the content of a change as a \emph{unified diff} (if you've never seen
287 a unified diff before, see section~\ref{sec:mq:patch} for an overview).
288 \interaction{tour.log-vp}
290 \section{All about command options}
292 Let's take a brief break from exploring Mercurial commands to discuss
293 a pattern in the way that they work; you may find this useful to keep
294 in mind as we continue our tour.
296 Mercurial has a consistent and straightforward approach to dealing
297 with the options that you can pass to commands. It follows the
298 conventions for options that are common to modern Linux and Unix
299 systems.
300 \begin{itemize}
301 \item Every option has a long name. For example, as we've already
302 seen, the \hgcmd{log} command accepts a \hgopt{log}{--rev} option.
303 \item Most options have short names, too. Instead of
304 \hgopt{log}{--rev}, we can use \hgopt{log}{-r}. (The reason that
305 some options don't have short names is that the options in question
306 are rarely used.)
307 \item Long options start with two dashes (e.g.~\hgopt{log}{--rev}),
308 while short options start with one (e.g.~\hgopt{log}{-r}).
309 \item Option naming and usage is consistent across commands. For
310 example, every command that lets you specify a changeset~ID or
311 revision number accepts both \hgopt{log}{-r} and \hgopt{log}{--rev}
312 arguments.
313 \end{itemize}
314 In the examples throughout this book, I use short options instead of
315 long. This just reflects my own preference, so don't read anything
316 significant into it.
318 Most commands that print output of some kind will print more output
319 when passed a \hggopt{-v} (or \hggopt{--verbose}) option, and less
320 when passed \hggopt{-q} (or \hggopt{--quiet}).
322 \section{Making and reviewing changes}
324 Now that we have a grasp of viewing history in Mercurial, let's take a
325 look at making some changes and examining them.
327 The first thing we'll do is isolate our experiment in a repository of
328 its own. We use the \hgcmd{clone} command, but we don't need to
329 clone a copy of the remote repository. Since we already have a copy
330 of it locally, we can just clone that instead. This is much faster
331 than cloning over the network, and cloning a local repository uses
332 less disk space in most cases, too.
333 \interaction{tour.reclone}
334 As an aside, it's often good practice to keep a ``pristine'' copy of a
335 remote repository around, which you can then make temporary clones of
336 to create sandboxes for each task you want to work on. This lets you
337 work on multiple tasks in parallel, each isolated from the others
338 until it's complete and you're ready to integrate it back. Because
339 local clones are so cheap, there's almost no overhead to cloning and
340 destroying repositories whenever you want.
342 In our \dirname{my-hello} repository, we have a file
343 \filename{hello.c} that contains the classic ``hello, world'' program.
344 Let's use the ancient and venerable \command{sed} command to edit this
345 file so that it prints a second line of output. (I'm only using
346 \command{sed} to do this because it's easy to write a scripted example
347 this way. Since you're not under the same constraint, you probably
348 won't want to use \command{sed}; simply use your preferred text editor to
349 do the same thing.)
350 \interaction{tour.sed}
352 Mercurial's \hgcmd{status} command will tell us what Mercurial knows
353 about the files in the repository.
354 \interaction{tour.status}
355 The \hgcmd{status} command prints no output for some files, but a line
356 starting with ``\texttt{M}'' for \filename{hello.c}. Unless you tell
357 it to, \hgcmd{status} will not print any output for files that have
358 not been modified.
360 The ``\texttt{M}'' indicates that Mercurial has noticed that we
361 modified \filename{hello.c}. We didn't need to \emph{inform}
362 Mercurial that we were going to modify the file before we started, or
363 that we had modified the file after we were done; it was able to
364 figure this out itself.
366 It's a little bit helpful to know that we've modified
367 \filename{hello.c}, but we might prefer to know exactly \emph{what}
368 changes we've made to it. To do this, we use the \hgcmd{diff}
369 command.
370 \interaction{tour.diff}
372 \section{Recording changes in a new changeset}
374 We can modify files, build and test our changes, and use
375 \hgcmd{status} and \hgcmd{diff} to review our changes, until we're
376 satisfied with what we've done and arrive at a natural stopping point
377 where we want to record our work in a new changeset.
379 The \hgcmd{commit} command lets us create a new changeset; we'll
380 usually refer to this as ``making a commit'' or ``committing''.
382 \subsection{Setting up a username}
384 When you try to run \hgcmd{commit} for the first time, it is not
385 guaranteed to succeed. Mercurial records your name and address with
386 each change that you commit, so that you and others will later be able
387 to tell who made each change. Mercurial tries to automatically figure
388 out a sensible username to commit the change with. It will attempt
389 each of the following methods, in order:
390 \begin{enumerate}
391 \item If you specify a \hgopt{commit}{-u} option to the \hgcmd{commit}
392 command on the command line, followed by a username, this is always
393 given the highest precedence.
394 \item If you have set the \envar{HGUSER} environment variable, this is
395 checked next.
396 \item If you create a file in your home directory called
397 \sfilename{.hgrc}, with a \rcitem{ui}{username} entry, that will be
398 used next. To see what the contents of this file should look like,
399 refer to section~\ref{sec:tour-basic:username} below.
400 \item If you have set the \envar{EMAIL} environment variable, this
401 will be used next.
402 \item Mercurial will query your system to find out your local user
403 name and host name, and construct a username from these components.
404 Since this often results in a username that is not very useful, it
405 will print a warning if it has to do this.
406 \end{enumerate}
407 If all of these mechanisms fail, Mercurial will fail, printing an
408 error message. In this case, it will not let you commit until you set
409 up a username.
411 You should think of the \envar{HGUSER} environment variable and the
412 \hgopt{commit}{-u} option to the \hgcmd{commit} command as ways to
413 \emph{override} Mercurial's default selection of username. For normal
414 use, the simplest and most robust way to set a username for yourself
415 is by creating a \sfilename{.hgrc} file; see below for details.
417 \subsubsection{Creating a Mercurial configuration file}
418 \label{sec:tour-basic:username}
420 To set a user name, use your favourite editor to create a file called
421 \sfilename{.hgrc} in your home directory. Mercurial will use this
422 file to look up your personalised configuration settings. The initial
423 contents of your \sfilename{.hgrc} should look like this.
424 \begin{codesample2}
425 # This is a Mercurial configuration file.
426 [ui]
427 username = Firstname Lastname <email.address@domain.net>
428 \end{codesample2}
429 The ``\texttt{[ui]}'' line begins a \emph{section} of the config file,
430 so you can read the ``\texttt{username = ...}'' line as meaning ``set
431 the value of the \texttt{username} item in the \texttt{ui} section''.
432 A section continues until a new section begins, or the end of the
433 file. Mercurial ignores empty lines and treats any text from
434 ``\texttt{\#}'' to the end of a line as a comment.
436 \subsubsection{Choosing a user name}
438 You can use any text you like as the value of the \texttt{username}
439 config item, since this information is for reading by other people,
440 but for interpreting by Mercurial. The convention that most people
441 follow is to use their name and email address, as in the example
442 above.
444 \begin{note}
445 Mercurial's built-in web server obfuscates email addresses, to make
446 it more difficult for the email harvesting tools that spammers use.
447 This reduces the likelihood that you'll start receiving more junk
448 email if you publish a Mercurial repository on the web.
449 \end{note}
451 \subsection{Writing a commit message}
453 When we commit a change, Mercurial drops us into a text editor, to
454 enter a message that will describe the modifications we've made in
455 this changeset. This is called the \emph{commit message}. It will be
456 a record for readers of what we did and why, and it will be printed by
457 \hgcmd{log} after we've finished committing.
458 \interaction{tour.commit}
460 The editor that the \hgcmd{commit} command drops us into will contain
461 an empty line, followed by a number of lines starting with
462 ``\texttt{HG:}''.
463 \begin{codesample2}
464 \emph{empty line}
465 HG: changed hello.c
466 \end{codesample2}
467 Mercurial ignores the lines that start with ``\texttt{HG:}''; it uses
468 them only to tell us which files it's recording changes to. Modifying
469 or deleting these lines has no effect.
471 \subsection{Writing a good commit message}
473 Since \hgcmd{log} only prints the first line of a commit message by
474 default, it's best to write a commit message whose first line stands
475 alone. Here's a real example of a commit message that \emph{doesn't}
476 follow this guideline, and hence has a summary that is not readable.
477 \begin{codesample2}
478 changeset: 73:584af0e231be
479 user: Censored Person <censored.person@example.org>
480 date: Tue Sep 26 21:37:07 2006 -0700
481 summary: include buildmeister/commondefs. Add an exports and install
482 \end{codesample2}
484 As far as the remainder of the contents of the commit message are
485 concerned, there are no hard-and-fast rules. Mercurial itself doesn't
486 interpret or care about the contents of the commit message, though
487 your project may have policies that dictate a certain kind of
488 formatting.
490 My personal preference is for short, but informative, commit messages
491 that tell me something that I can't figure out with a quick glance at
492 the output of \hgcmdargs{log}{--patch}.
494 \subsection{Aborting a commit}
496 If you decide that you don't want to commit while in the middle of
497 editing a commit message, simply exit from your editor without saving
498 the file that it's editing. This will cause nothing to happen to
499 either the repository or the working directory.
501 If we run the \hgcmd{commit} command without any arguments, it records
502 all of the changes we've made, as reported by \hgcmd{status} and
503 \hgcmd{diff}.
505 \subsection{Admiring our new handiwork}
507 Once we've finished the commit, we can use the \hgcmd{tip} command to
508 display the changeset we just created. This command produces output
509 that is identical to \hgcmd{log}, but it only displays the newest
510 revision in the repository.
511 \interaction{tour.tip}
512 We refer to the newest revision in the repository as the tip revision,
513 or simply the tip.
515 \section{Sharing changes}
517 We mentioned earlier that repositories in Mercurial are
518 self-contained. This means that the changeset we just created exists
519 only in our \dirname{my-hello} repository. Let's look at a few ways
520 that we can propagate this change into other repositories.
522 \subsection{Pulling changes from another repository}
523 \label{sec:tour:pull}
525 To get started, let's clone our original \dirname{hello} repository,
526 which does not contain the change we just committed. We'll call our
527 temporary repository \dirname{hello-pull}.
528 \interaction{tour.clone-pull}
530 We'll use the \hgcmd{pull} command to bring changes from
531 \dirname{my-hello} into \dirname{hello-pull}. However, blindly
532 pulling unknown changes into a repository is a somewhat scary
533 prospect. Mercurial provides the \hgcmd{incoming} command to tell us
534 what changes the \hgcmd{pull} command \emph{would} pull into the
535 repository, without actually pulling the changes in.
536 \interaction{tour.incoming}
537 (Of course, someone could cause more changesets to appear in the
538 repository that we ran \hgcmd{incoming} in, before we get a chance to
539 \hgcmd{pull} the changes, so that we could end up pulling changes that we
540 didn't expect.)
542 Bringing changes into a repository is a simple matter of running the
543 \hgcmd{pull} command, and telling it which repository to pull from.
544 \interaction{tour.pull}
545 As you can see from the before-and-after output of \hgcmd{tip}, we
546 have successfully pulled changes into our repository. There remains
547 one step before we can see these changes in the working directory.
549 \subsection{Updating the working directory}
551 We have so far glossed over the relationship between a repository and
552 its working directory. The \hgcmd{pull} command that we ran in
553 section~\ref{sec:tour:pull} brought changes into the repository, but
554 if we check, there's no sign of those changes in the working
555 directory. This is because \hgcmd{pull} does not (by default) touch
556 the working directory. Instead, we use the \hgcmd{update} command to
557 do this.
558 \interaction{tour.update}
560 It might seem a bit strange that \hgcmd{pull} doesn't update the
561 working directory automatically. There's actually a good reason for
562 this: you can use \hgcmd{update} to update the working directory to
563 the state it was in at \emph{any revision} in the history of the
564 repository. If you had the working directory updated to an old
565 revision---to hunt down the origin of a bug, say---and ran a
566 \hgcmd{pull} which automatically updated the working directory to a
567 new revision, you might not be terribly happy.
569 However, since pull-then-update is such a common thing to do,
570 Mercurial lets you combine the two by passing the \hgopt{pull}{-u}
571 option to \hgcmd{pull}.
572 \begin{codesample2}
573 hg pull -u
574 \end{codesample2}
575 If you look back at the output of \hgcmd{pull} in
576 section~\ref{sec:tour:pull} when we ran it without \hgopt{pull}{-u},
577 you can see that it printed a helpful reminder that we'd have to take
578 an explicit step to update the working directory:
579 \begin{codesample2}
580 (run 'hg update' to get a working copy)
581 \end{codesample2}
583 To find out what revision the working directory is at, use the
584 \hgcmd{parents} command.
585 \interaction{tour.parents}
586 If you look back at figure~\ref{fig:tour-basic:history}, you'll see
587 arrows connecting each changeset. The node that the arrow leads
588 \emph{from} in each case is a parent, and the node that the arrow
589 leads \emph{to} is its child. The working directory has a parent in
590 just the same way; this is the changeset that the working directory
591 currently contains.
593 To update the working directory to a particular revision, give a
594 revision number or changeset~ID to the \hgcmd{update} command.
595 \interaction{tour.older}
596 If you omit an explicit revision, \hgcmd{update} will update to the
597 tip revision, as shown by the second call to \hgcmd{update} in the
598 example above.
600 \subsection{Pushing changes to another repository}
602 Mercurial lets us push changes to another repository, from the
603 repository we're currently visiting. As with the example of
604 \hgcmd{pull} above, we'll create a temporary repository to push our
605 changes into.
606 \interaction{tour.clone-push}
607 The \hgcmd{outgoing} command tells us what changes would be pushed
608 into another repository.
609 \interaction{tour.outgoing}
610 And the \hgcmd{push} command does the actual push.
611 \interaction{tour.push}
612 As with \hgcmd{pull}, the \hgcmd{push} command does not update the
613 working directory in the repository that it's pushing changes into.
614 (Unlike \hgcmd{pull}, \hgcmd{push} does not provide a \texttt{-u}
615 option that updates the other repository's working directory.)
617 What happens if we try to pull or push changes and the receiving
618 repository already has those changes? Nothing too exciting.
619 \interaction{tour.push.nothing}
621 \subsection{Sharing changes over a network}
623 The commands we have covered in the previous few sections are not
624 limited to working with local repositories. Each works in exactly the
625 same fashion over a network connection; simply pass in a URL instead
626 of a local path.
627 \interaction{tour.outgoing.net}
628 In this example, we can see what changes we could push to the remote
629 repository, but the repository is understandably not set up to let
630 anonymous users push to it.
631 \interaction{tour.push.net}
633 %%% Local Variables:
634 %%% mode: latex
635 %%% TeX-master: "00book"
636 %%% End: