This is Info file ../../info/xemacs.info, produced by Makeinfo version 1.68 from the input file xemacs.texi. INFO-DIR-SECTION XEmacs Editor START-INFO-DIR-ENTRY * XEmacs: (xemacs). XEmacs Editor. END-INFO-DIR-ENTRY This file documents the XEmacs editor. Copyright (C) 1985, 1986, 1988 Richard M. Stallman. Copyright (C) 1991, 1992, 1993, 1994 Lucid, Inc. Copyright (C) 1993, 1994 Sun Microsystems, Inc. Copyright (C) 1995 Amdahl Corporation. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" may be included in a translation approved by the author instead of in the original English.  File: xemacs.info, Node: Backup Copying, Prev: Backup Deletion, Up: Backup Copying vs. Renaming .................... You can make backup files by copying the old file or by renaming it. This makes a difference when the old file has multiple names. If you rename the old file into the backup file, the alternate names become names for the backup file. If you copy the old file instead, the alternate names remain names for the file that you are editing, and the contents accessed by those names will be the new contents. How you make a backup file may also affect the file's owner and group. If you use copying, they do not change. If renaming is used, you become the file's owner, and the file's group becomes the default (different operating systems have different defaults for the group). Having the owner change is usually a good idea, because then the owner is always the person who last edited the file. Occasionally there is a file whose owner should not change. Since most files should change owners, it is a good idea to use local variable lists to set `backup-by-copying-when-mismatch' for the special cases where the owner should not change (*note File Variables::.). Three variables control the choice of renaming or copying. Normally, renaming is done. If the variable `backup-by-copying' is non-`nil', copying is used. Otherwise, if the variable `backup-by-copying-when-linked' is non-`nil', copying is done for files that have multiple names, but renaming may still be done when the file being edited has only one name. If the variable `backup-by-copying-when-mismatch' is non-`nil', copying is done if renaming would cause the file's owner or group to change.  File: xemacs.info, Node: Interlocking, Prev: Backup, Up: Saving Protection Against Simultaneous Editing --------------------------------------- Simultaneous editing occurs when two users visit the same file, both make changes, and both save their changes. If no one was informed that this was happening, and you saved first, you would later find that your changes were lost. On some systems, Emacs notices immediately when the second user starts to change a file already being edited, and issues a warning. When this is not possible, or if the second user has started to change the file despite the warning, Emacs checks when the file is saved, and issues a second warning when a user is about to overwrite a file containing another user's changes. If you are the user editing the file, you can take corrective action at this point and prevent actual loss of work. When you make the first modification in an Emacs buffer that is visiting a file, Emacs records that you have locked the file. (It does this by writing another file in a directory reserved for this purpose.) The lock is removed when you save the changes. The idea is that the file is locked whenever the buffer is modified. If you begin to modify the buffer while the visited file is locked by someone else, this constitutes a collision, and Emacs asks you what to do. It does this by calling the Lisp function `ask-user-about-lock', which you can redefine to customize what it does. The standard definition of this function asks you a question and accepts three possible answers: `s' Steal the lock. Whoever was already changing the file loses the lock, and you get the lock. `p' Proceed. Go ahead and edit the file despite its being locked by someone else. `q' Quit. This causes an error (`file-locked') and the modification you were trying to make in the buffer does not actually take place. Note that locking works on the basis of a file name; if a file has multiple names, Emacs does not realize that the two names are the same file and cannot prevent two users from editing it simultaneously under different names. However, basing locking on names means that Emacs can interlock the editing of new files that do not really exist until they are saved. Some systems are not configured to allow Emacs to make locks. On these systems, Emacs cannot detect trouble in advance, but it can still detect it in time to prevent you from overwriting someone else's changes. Every time Emacs saves a buffer, it first checks the last-modification date of the existing file on disk to see that it has not changed since the file was last visited or saved. If the date does not match, it implies that changes were made in the file in some other way, and these changes are about to be lost if Emacs actually does save. To prevent this, Emacs prints a warning message and asks for confirmation before saving. Occasionally you will know why the file was changed and know that it does not matter; then you can answer `yes' and proceed. Otherwise, you should cancel the save with `C-g' and investigate the situation. The first thing you should do when notified that simultaneous editing has already taken place is to list the directory with `C-u C-x C-d' (*note Directory Listing: ListDir.). This will show the file's current author. You should attempt to contact that person and ask him not to continue editing. Often the next step is to save the contents of your Emacs buffer under a different name, and use `diff' to compare the two files. Simultaneous editing checks are also made when you visit a file that is already visited with `C-x C-f' and when you start to modify a file. This is not strictly necessary, but it is useful to find out about such a problem as early as possible, when corrective action takes less work. Another way to protect your file is to set the read, write, and executable permissions for the file. Use the function `set-default-file-modes' to set the UNIX `umask' value to the NMASK argument. The `umask' value is the default protection mode for new files.  File: xemacs.info, Node: Reverting, Next: Auto Save, Prev: Saving, Up: Files Reverting a Buffer ================== If you have made extensive changes to a file and then change your mind about them, you can get rid of all changes by reading in the previous version of the file. To do this, use `M-x revert-buffer', which operates on the current buffer. Since reverting a buffer can result in very extensive changes, you must confirm it with `yes'. If the current buffer has been auto-saved more recently than it has been saved explicitly, `revert-buffer' offers to read the auto save file instead of the visited file (*note Auto Save::.). Emacs asks you about the auto-save file before the request for confirmation of the `revert-buffer' operation, and demands `y' or `n' as an answer. If you have started to type `yes' for confirmation without realizing that the auto-save question was going to be asked, the `y' will answer that question, but the `es' will not be valid confirmation. This gives you a chance to cancel the operation with `C-g' and try again with the answers you really intend. `revert-buffer' keeps point at the same distance (measured in characters) from the beginning of the file. If the file was edited only slightly, you will be at approximately the same piece of text after reverting as before. If you have made more extensive changes, the value of point in the old file may bring you to a totally different piece of text than your last editing point. A buffer reverted from its visited file is marked "not modified" until you make a change. Some kinds of buffers whose contents reflect data bases other than files, such as Dired buffers, can also be reverted. For them, reverting means recalculating their contents from the appropriate data. Buffers created randomly with `C-x b' cannot be reverted; `revert-buffer' reports an error when asked to do so.  File: xemacs.info, Node: Auto Save, Next: Version Control, Prev: Reverting, Up: Files Auto-Saving: Protection Against Disasters ========================================= Emacs saves all the visited files from time to time (based on counting your keystrokes) without being asked. This is called "auto-saving". It prevents you from losing more than a limited amount of work if the system crashes. When Emacs determines it is time for auto-saving, each buffer is considered and is auto-saved if auto-saving is turned on for it and it has changed since the last time it was auto-saved. If any auto-saving is done, the message `Auto-saving...' is displayed in the echo area until auto-saving is finished. Errors occurring during auto-saving are caught so that they do not interfere with the execution of commands you have been typing. * Menu: * Files: Auto Save Files. * Control: Auto Save Control. * Recover:: Recovering text from auto-save files.  File: xemacs.info, Node: Auto Save Files, Next: Auto Save Control, Prev: Auto Save, Up: Auto Save Auto-Save Files --------------- Auto-saving does not normally write to the files you visited, because it can be undesirable to save a program that is in an inconsistent state when you have made only half of a planned change. Instead, auto-saving is done in a different file called the "auto-save file", and the visited file is changed only when you save explicitly, for example, with `C-x C-s'. Normally, the name of the auto-save file is generated by appending `#' to the front and back of the visited file name. Thus, a buffer visiting file `foo.c' would be auto-saved in a file `#foo.c#'. Most buffers that are not visiting files are auto-saved only if you request it explicitly; when they are auto-saved, the auto-save file name is generated by appending `#%' to the front and `#' to the back of buffer name. For example, the `*mail*' buffer in which you compose messages to be sent is auto-saved in a file named `#%*mail*#'. Names of auto-save files are generated this way unless you customize the functions `make-auto-save-file-name' and `auto-save-file-name-p' to do something different. The file name to be used for auto-saving a buffer is calculated at the time auto-saving is turned on in that buffer. If you want auto-saving to be done in the visited file, set the variable `auto-save-visited-file-name' to be non-`nil'. In this mode, there is really no difference between auto-saving and explicit saving. Emacs deletes a buffer's auto-save file when you explicitly save the buffer. To inhibit the deletion, set the variable `delete-auto-save-files' to `nil'. Changing the visited file name with `C-x C-w' or `set-visited-file-name' renames any auto-save file to correspond to the new visited name.  File: xemacs.info, Node: Auto Save Control, Next: Recover, Prev: Auto Save Files, Up: Auto Save Controlling Auto-Saving ----------------------- Each time you visit a file, auto-saving is turned on for that file's buffer if the variable `auto-save-default' is non-`nil' (but not in batch mode; *note Entering Emacs::.). The default for this variable is `t', so Emacs auto-saves buffers that visit files by default. You can use the command `M-x auto-save-mode' to turn auto-saving for a buffer on or off. Like other minor mode commands, `M-x auto-save-mode' turns auto-saving on with a positive argument, off with a zero or negative argument; with no argument, it toggles. Emacs performs auto-saving periodically based on counting how many characters you have typed since the last time auto-saving happened. The variable `auto-save-interval' specifies the number of characters between auto-saves. By default, it is 300. Emacs also auto-saves whenever you call the function `do-auto-save'. Emacs also does auto-saving whenever it gets a fatal error. This includes killing the Emacs job with a shell command such as `kill -emacs', or disconnecting a phone line or network connection. You can set the number of seconds of idle time before an auto-save is done. Setting the value of the variable `auto-save-timeout' to zero or `nil' will disable auto-saving due to idleness. The actual amount of idle time between auto-saves is logarithmically related to the size of the current buffer. This variable is the number of seconds after which an auto-save will happen when the current buffer is 50k or less; the timeout will be 2 1/4 times this in a 200k buffer, 3 3/4 times this in a 1000k buffer, and 4 1/2 times this in a 2000k buffer. For this variable to have any effect, you must do `(require 'timer)'.  File: xemacs.info, Node: Recover, Prev: Auto Save Control, Up: Auto Save Recovering Data from Auto-Saves ------------------------------- If you want to use the contents of an auto-save file to recover from a loss of data, use the command `M-x recover-file FILE '. Emacs visits FILE and then (after your confirmation) restores the contents from the auto-save file `#FILE#'. You can then save the file with `C-x C-s' to put the recovered text into FILE itself. For example, to recover file `foo.c' from its auto-save file `#foo.c#', do: M-x recover-file foo.c C-x C-s Before asking for confirmation, `M-x recover-file' displays a directory listing describing the specified file and the auto-save file, so you can compare their sizes and dates. If the auto-save file is older, `M-x recover-file' does not offer to read it. Auto-saving is disabled by `M-x recover-file' because using this command implies that the auto-save file contains valuable data from a past session. If you save the data in the visited file and then go on to make new changes, turn auto-saving back on with `M-x auto-save-mode'.  File: xemacs.info, Node: Version Control, Next: ListDir, Prev: Auto Save, Up: Files Version Control =============== "Version control systems" are packages that can record multiple versions of a source file, usually storing the unchanged parts of the file just once. Version control systems also record history information such as the creation time of each version, who created it, and a description of what was changed in that version. The GNU project recommends the version control system known as RCS, which is free software and available from the Free Software Foundation. Emacs supports use of either RCS or SCCS (a proprietary, but widely used, version control system that is not quite as powerful as RCS) through a facility called VC. The same Emacs commands work with either RCS or SCCS, so you hardly have to know which one of them you are using. * Menu: * Concepts of VC:: Basic version control information; checking files in and out. * Editing with VC:: Commands for editing a file maintained with version control. * Variables for Check-in/out:: Variables that affect the commands used to check files in or out. * Log Entries:: Logging your changes. * Change Logs and VC:: Generating a change log file from log entries. * Old Versions:: Examining and comparing old versions. * VC Status:: Commands to view the VC status of files and look at log entries. * Renaming and VC:: A command to rename both the source and master file correctly. * Snapshots:: How to make and use snapshots, a set of file versions that can be treated as a unit. * Version Headers:: Inserting version control headers into working files.  File: xemacs.info, Node: Concepts of VC, Next: Editing with VC, Prev: Version Control, Up: Version Control Concepts of Version Control --------------------------- When a file is under version control, we also say that it is "registered" in the version control system. Each registered file has a corresponding "master file" which represents the file's present state plus its change history, so that you can reconstruct from it either the current version or any specified earlier version. Usually the master file also records a "log entry" for each version describing what was changed in that version. The file that is maintained under version control is sometimes called the "work file" corresponding to its master file. To examine a file, you "check it out". This extracts a version of the source file (typically, the most recent) from the master file. If you want to edit the file, you must check it out "locked". Only one user can do this at a time for any given source file. (This kind of locking is completely unrelated to the locking that Emacs uses to detect simultaneous editing of a file.) When you are done with your editing, you must "check in" the new version. This records the new version in the master file, and unlocks the source file so that other people can lock it and thus modify it. Checkin and checkout are the basic operations of version control. You can do both of them with a single Emacs command: `C-x C-q' (`vc-toggle-read-only'). A "snapshot" is a coherent collection of versions of the various files that make up a program. *Note Snapshots::.  File: xemacs.info, Node: Editing with VC, Next: Variables for Check-in/out, Prev: Concepts of VC, Up: Version Control Editing with Version Control ---------------------------- When you visit a file that is maintained using version control, the mode line displays `RCS' or `SCCS' to inform you that version control is in use, and also (in case you care) which low-level system the file is actually stored in. Normally, such a source file is read-only, and the mode line indicates this with `%%'. With RCS, the mode line also indicates the number of the head version, which is normally also the version you are looking at. These are the commands for editing a file maintained with version control: `C-x C-q' Check the visited file in or out. `C-x v u' Revert the buffer and the file to the last checked in version. `C-x v c' Remove the last-entered change from the master for the visited file. This undoes your last check-in. `C-x v i' Register the visited file in version control. (`C-x v' is the prefix key for version control commands; all of these commands except for `C-x C-q' start with `C-x v'.) When you want to modify a file maintained with version control, type `C-x C-q' (`vc-toggle-read-only'). This "checks out" the file, and tells RCS or SCCS to lock the file. This means making the file writable for you (but not for anyone else). When you are finished editing the file, type `C-x C-q' again. When used on a file that is checked out, this command checks the file in. But check-in does not start immediately; first, you must enter the "log entry"--a description of the changes in the new version. `C-x C-q' pops up a buffer for you to enter this in. When you are finished typing in the log entry, type `C-c C-c' to terminate it; this is when actual check-in takes place. Once you have checked in your changes, the file is unlocked, so that other users can lock it and modify it. Emacs does not save backup files for source files that are maintained with version control. If you want to make backup files despite version control, set the variable `vc-make-backup-files' to a non-`nil' value. Normally the work file exists all the time, whether it is locked or not. If you set `vc-keep-workfiles' to `nil', then checking in a new version with `C-x C-q' deletes the work file; but any attempt to visit the file with Emacs creates it again. It is not impossible to lock a file that someone else has locked. If you try to check out a file that is locked, `C-x C-q' asks you whether you want to "steal the lock." If you say yes, the file becomes locked by you, but a message is sent to the person who had formerly locked the file, to inform him of what has happened. The mode line indicates that a file is locked by someone else by displaying the login name of that person, before the version number. If you want to discard your current set of changes and revert to the last version checked in, use `C-x v u' (`vc-revert-buffer'). This cancels your last check-out, leaving the file unlocked. If you want to make a different set of changes, you must first check the file out again. `C-x v u' requires confirmation, unless it sees that you haven't made any changes since the last checked-in version. `C-x v u' is also the command to use if you lock a file and then don't actually change it. You can cancel a change after checking it in, with `C-x v c' (`vc-cancel-version'). This command discards all record of the most recent checked in version, so be careful about using it. It requires confirmation with `yes'. By default, `C-x v c' reverts your workfile and buffer to the previous version (the one that precedes the version that is deleted), but you can prevent the reversion by giving the command a prefix argument. Then the buffer does not change. This command with a prefix argument is useful when you have checked in a change and then discover a trivial error in it; you can cancel the erroneous check-in, fix the error, and repeat the check-in. Be careful when invoking `C-x v c', as it is easy to throw away a lot of work with it. To help you be careful, this command always requires confirmation with `yes'. You can register the visited file for version control using `C-x v i' (`vc-register'). If the variable `vc-default-back-end' is non-`nil', it specifies which version control system to use; otherwise, this uses RCS if it is installed on your system and SCCS if not. After `C-x v i', the file is unlocked and read-only. Type `C-x C-q' if you wish to edit it. By default, the initial version number is 1.1. If you want to use a different number, give `C-x v i' a prefix argument; then it reads the initial version number using the minibuffer. If `vc-initial-comment' is non-`nil', `C-x v i' reads an initial comment (much like a log entry) to describe the purpose of this source file. To specify the version number for a subsequent checkin, use the command `C-u C-x v v'. `C-x v v' (`vc-next-action') is the command that `C-x C-q' uses to do the "real work" when the visited file uses version control. When used for checkin, and given a prefix argument, it reads the version number with the minibuffer.  File: xemacs.info, Node: Variables for Check-in/out, Next: Log Entries, Prev: Editing with VC, Up: Version Control Variables Affecting Check-in and Check-out ------------------------------------------ If `vc-suppress-confirm' is non-`nil', then `C-x C-q' and `C-x v i' can save the current buffer without asking, and `C-x v u' also operates without asking for confirmation. (This variable does not affect `C-x v c'; that is so drastic that it should always ask for confirmation.) VC mode does much of its work by running the shell commands for RCS and SCCS. If `vc-command-messages' is non-`nil', VC displays messages to indicate which shell commands it runs, and additional messages when the commands finish. Normally, VC assumes that it can deduce the locked/unlocked state of files by looking at the file permissions of the work file; this is fast. However, if the `RCS' or `SCCS' subdirectory is actually a symbolic link, then VC does not trust the file permissions to reflect this status. You can specify the criterion for whether to trust the file permissions by setting the variable `vc-mistrust-permissions'. Its value may be `t' (always mistrust the file permissions and check the master file), `nil' (always trust the file permissions), or a function of one argument which makes the decision. The argument is the directory name of the `RCS' or `SCCS' subdirectory. A non-`nil' value from the function says to mistrust the file permissions. If you find that the file permissions of work files are changed erroneously, set `vc-mistrust-permissions' to `t'. Then VC always checks the master file to determine the file's status. You can specify additional directories to search for version control programs by setting the variable `vc-path'. These directories are searched before the usual search path. The proper result usually happens automatically.  File: xemacs.info, Node: Log Entries, Next: Change Logs and VC, Prev: Variables for Check-in/out, Up: Version Control Log Entries ----------- When you're editing an initial comment or log entry for inclusion in a master file, finish your entry by typing `C-c C-c'. `C-c C-c' Finish the comment edit normally (`vc-finish-logentry'). This finishes check-in. To abort check-in, just don't type `C-c C-c' in that buffer. You can switch buffers and do other editing. As long as you don't try to check in another file, the entry you were editing remains in its buffer, and you can go back to that buffer at any time to complete the check-in. If you change several source files for the same reason, it is often convenient to specify the same log entry for many of the files. To do this, use the history of previous log entries. The commands `M-n', `M-p', `M-s' and `M-r' for doing this work just like the minibuffer history commands (except that these versions are used outside the minibuffer). Each time you check in a file, the log entry buffer is put into VC Log mode, which involves running two hooks: `text-mode-hook' and `vc-log-mode-hook'.  File: xemacs.info, Node: Change Logs and VC, Next: Old Versions, Prev: Log Entries, Up: Version Control Change Logs and VC ------------------ If you use RCS for a program and also maintain a change log file for it (*note Change Log::.), you can generate change log entries automatically from the version control log entries: `C-x v a' Visit the current directory's change log file and create new entries for versions checked in since the most recent entry in the change log file (`vc-update-change-log'). This command works with RCS only; it does not work with SCCS. For example, suppose the first line of `ChangeLog' is dated 10 April 1992, and that the only check-in since then was by Nathaniel Bowditch to `rcs2log' on 8 May 1992 with log text `Ignore log messages that start with `#'.'. Then `C-x v a' visits `ChangeLog' and inserts text like this: Fri May 8 21:45:00 1992 Nathaniel Bowditch (nat@apn.org) * rcs2log: Ignore log messages that start with `#'. You can then edit the new change log entry further as you wish. Normally, the log entry for file `foo' is displayed as `* foo: TEXT OF LOG ENTRY'. The `:' after `foo' is omitted if the text of the log entry starts with `(FUNCTIONNAME): '. For example, if the log entry for `vc.el' is `(vc-do-command): Check call-process status.', then the text in `ChangeLog' looks like this: Wed May 6 10:53:00 1992 Nathaniel Bowditch (nat@apn.org) * vc.el (vc-do-command): Check call-process status. When `C-x v a' adds several change log entries at once, it groups related log entries together if they all are checked in by the same author at nearly the same time. If the log entries for several such files all have the same text, it coalesces them into a single entry. For example, suppose the most recent checkins have the following log entries: For `vc.texinfo': Fix expansion typos. For `vc.el': Don't call expand-file-name. For `vc-hooks.el': Don't call expand-file-name. They appear like this in `ChangeLog': Wed Apr 1 08:57:59 1992 Nathaniel Bowditch (nat@apn.org) * vc.texinfo: Fix expansion typos. * vc.el, vc-hooks.el: Don't call expand-file-name. Normally, `C-x v a' separates log entries by a blank line, but you can mark several related log entries to be clumped together (without an intervening blank line) by starting the text of each related log entry with a label of the form `{CLUMPNAME} '. The label itself is not copied to `ChangeLog'. For example, suppose the log entries are: For `vc.texinfo': {expand} Fix expansion typos. For `vc.el': {expand} Don't call expand-file-name. For `vc-hooks.el': {expand} Don't call expand-file-name. Then the text in `ChangeLog' looks like this: Wed Apr 1 08:57:59 1992 Nathaniel Bowditch (nat@apn.org) * vc.texinfo: Fix expansion typos. * vc.el, vc-hooks.el: Don't call expand-file-name. A log entry whose text begins with `#' is not copied to `ChangeLog'. For example, if you merely fix some misspellings in comments, you can log the change with an entry beginning with `#' to avoid putting such trivia into `ChangeLog'.  File: xemacs.info, Node: Old Versions, Next: VC Status, Prev: Change Logs and VC, Up: Version Control Examining And Comparing Old Versions ------------------------------------ `C-x v ~ VERSION ' Examine version VERSION of the visited file, in a buffer of its own (`vc-version-other-window'). `C-x v =' Compare the current buffer contents with the latest checked-in version of the file. `C-u C-x v = FILE OLDVERS NEWVERS ' Compare the specified two versions of FILE. You can examine any version of a file by first visiting it, and then using `C-x v ~ VERSION ' (`vc-version-other-window'). This puts the text of version VERSION in a file named `FILENAME.~VERSION~', then visits it in a separate window. To compare two versions of a file, use the command `C-x v =' (`vc-diff'). Plain `C-x v =' compares the current buffer contents (saving them in the file if necessary) with the last checked-in version of the file. With a prefix argument, `C-x v =' reads a file name and two version numbers, then compares those versions of the specified file. If you supply a directory name instead of the name of a work file, this command compares the two specified versions of all registered files in that directory and its subdirectories. You can also specify a snapshot name (*note Snapshots::.) instead of one or both version numbers. You can specify a checked-in version by its number; you can specify the most recent checked-in version with an empty version number. This command works by running the `vcdiff' utility, getting the options from the variable `diff-switches'. It displays the output in a special buffer in another window. Unlike the `M-x diff' command, `C-x v =' does not try to find the changes in the old and new versions. This is because one or both versions normally do not exist as files. They exist only in the records of the master file. *Note Comparing Files::, for more information about `M-x diff'.  File: xemacs.info, Node: VC Status, Next: Renaming and VC, Prev: Old Versions, Up: Version Control VC Status Commands ------------------ To view the detailed version control status and history of a file, type `C-x v l' (`vc-print-log'). It displays the history of changes to the current file, including the text of the log entries. The output appears in a separate window. When you are working on a large program, it's often useful to find all the files that are currently locked, or all the files maintained in version control at all. You can use `C-x v d' (`vc-directory') to show all the locked files in or beneath the current directory. This includes all files that are locked by any user. `C-u C-x v d' lists all files in or beneath the current directory that are maintained with version control. The list of files is displayed as a buffer that uses an augmented Dired mode. The names of the users locking various files are shown (in parentheses) in place of the owner and group. All the normal Dired commands work in this buffer. Most interactive VC commands work also, and apply to the file name on the current line. The `C-x v v' command (`vc-next-action'), when used in the augmented Dired buffer, operates on all the marked files (or the file on the current line). If it operates on more than one file, it handles each file according to its current state; thus, it may check out one file and check in another (because it is already checked out). If it has to check in any files, it reads a single log entry, then uses that text for all the files being checked in. This can be convenient for registering or checking in several files at once, as part of the same change.  File: xemacs.info, Node: Renaming and VC, Next: Snapshots, Prev: VC Status, Up: Version Control Renaming VC Work Files and Master Files --------------------------------------- When you rename a registered file, you must also rename its master file correspondingly to get proper results. Use `vc-rename-file' to rename the source file as you specify, and rename its master file accordingly. It also updates any snapshots (*note Snapshots::.) that mention the file, so that they use the new name; despite this, the snapshot thus modified may not completely work (*note Snapshot Caveats::.). You cannot use `vc-rename-file' on a file that is locked by someone else.  File: xemacs.info, Node: Snapshots, Next: Version Headers, Prev: Renaming and VC, Up: Version Control Snapshots --------- A "snapshot" is a named set of file versions (one for each registered file) that you can treat as a unit. One important kind of snapshot is a "release", a (theoretically) stable version of the system that is ready for distribution to users. * Menu: * Making Snapshots:: The snapshot facilities. * Snapshot Caveats:: Things to be careful of when using snapshots.  File: xemacs.info, Node: Making Snapshots, Next: Snapshot Caveats, Prev: Snapshots, Up: Snapshots Making and Using Snapshots .......................... There are two basic commands for snapshots; one makes a snapshot with a given name, the other retrieves a named snapshot. `C-x v s NAME ' Define the last saved versions of every registered file in or under the current directory as a snapshot named NAME (`vc-create-snapshot'). `C-x v r NAME ' Check out all registered files at or below the current directory level using whatever versions correspond to the snapshot NAME (`vc-retrieve-snapshot'). This command reports an error if any files are locked at or below the current directory, without changing anything; this is to avoid overwriting work in progress. A snapshot uses a very small amount of resources--just enough to record the list of file names and which version belongs to the snapshot. Thus, you need not hesitate to create snapshots whenever they are useful. You can give a snapshot name as an argument to `C-x v =' or `C-x v ~' (*note Old Versions::.). Thus, you can use it to compare a snapshot against the current files, or two snapshots against each other, or a snapshot against a named version.  File: xemacs.info, Node: Snapshot Caveats, Prev: Making Snapshots, Up: Snapshots Snapshot Caveats ................ VC's snapshot facilities are modeled on RCS's named-configuration support. They use RCS's native facilities for this, so under VC snapshots made using RCS are visible even when you bypass VC. For SCCS, VC implements snapshots itself. The files it uses contain name/file/version-number triples. These snapshots are visible only through VC. A snapshot is a set of checked-in versions. So make sure that all the files are checked in and not locked when you make a snapshot. File renaming and deletion can create some difficulties with snapshots. This is not a VC-specific problem, but a general design issue in version control systems that no one has solved very well yet. If you rename a registered file, you need to rename its master along with it (the command `vc-rename-file' does this automatically). If you are using SCCS, you must also update the records of the snapshot, to mention the file by its new name (`vc-rename-file' does this, too). An old snapshot that refers to a master file that no longer exists under the recorded name is invalid; VC can no longer retrieve it. It would be beyond the scope of this manual to explain enough about RCS and SCCS to explain how to update the snapshots by hand. Using `vc-rename-file' makes the snapshot remain valid for retrieval, but it does not solve all problems. For example, some of the files in the program probably refer to others by name. At the very least, the makefile probably mentions the file that you renamed. If you retrieve an old snapshot, the renamed file is retrieved under its new name, which is not the name that the makefile expects. So the program won't really work as retrieved.  File: xemacs.info, Node: Version Headers, Prev: Snapshots, Up: Version Control Inserting Version Control Headers --------------------------------- Sometimes it is convenient to put version identification strings directly into working files. Certain special strings called "version headers" are replaced in each successive version by the number of that version. You can use the `C-x v h' command (`vc-insert-headers') to insert a suitable header string. `C-x v h' Insert headers in a file for use with your version-control system. The default header string is `\$Id\$' for RCS and `\%W\%' for SCCS. (The actual strings inserted do not have the backslashes in them. They were placed in the Info source file so that the strings don't get interpreted as version-control headers when the Info source files are maintained under version control.) You can specify other headers to insert by setting the variable `vc-header-alist'. Its value is a list of elements of the form `(PROGRAM . STRING)' where PROGRAM is `RCS' or `SCCS' and STRING is the string to use. Instead of a single string, you can specify a list of strings; then each string in the list is inserted as a separate header on a line of its own. It is often necessary to use "superfluous" backslashes when writing the strings that you put in this variable. This is to prevent the string in the constant from being interpreted as a header itself if the Emacs Lisp file containing it is maintained with version control. Each header is inserted surrounded by tabs, inside comment delimiters, on a new line at the start of the buffer. Normally the ordinary comment start and comment end strings of the current mode are used, but for certain modes, there are special comment delimiters for this purpose; the variable `vc-comment-alist' specifies them. Each element of this list has the form `(MODE STARTER ENDER)'. The variable `vc-static-header-alist' specifies further strings to add based on the name of the buffer. Its value should be a list of elements of the form `(REGEXP . FORMAT)'. Whenever REGEXP matches the buffer name, FORMAT is inserted as part of the header. A header line is inserted for each element that matches the buffer name, and for each string specified by `vc-header-alist'. The header line is made by processing the string from `vc-header-alist' with the format taken from the element. The default value for `vc-static-header-alist' is: (("\\.c$" . "\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\ #endif /* lint */\n")) which specifies insertion of a string of this form: #ifndef lint static char vcid[] = "STRING"; #endif /* lint */  File: xemacs.info, Node: ListDir, Next: Comparing Files, Prev: Version Control, Up: Files Listing a File Directory ======================== Files are organized by Unix into "directories". A "directory listing" is a list of all the files in a directory. Emacs provides directory listings in brief format (file names only) and verbose format (sizes, dates, and authors included). `C-x C-d DIR-OR-PATTERN' Print a brief directory listing (`list-directory'). `C-u C-x C-d DIR-OR-PATTERN' Print a verbose directory listing. To print a directory listing, use `C-x C-d' (`list-directory'). This command prompts in the minibuffer for a file name which is either a directory to be listed or pattern containing wildcards for the files to be listed. For example, C-x C-d /u2/emacs/etc lists all the files in directory `/u2/emacs/etc'. An example of specifying a file name pattern is: C-x C-d /u2/emacs/src/*.c Normally, `C-x C-d' prints a brief directory listing containing just file names. A numeric argument (regardless of value) tells it to print a verbose listing (like `ls -l'). Emacs obtains the text of a directory listing by running `ls' in an inferior process. Two Emacs variables control the switches passed to `ls': `list-directory-brief-switches' is a string giving the switches to use in brief listings (`"-CF"' by default). `list-directory-verbose-switches' is a string giving the switches to use in a verbose listing (`"-l"' by default). The variable `directory-abbrev-alist' is an alist of abbreviations for file directories. The list consists of elements of the form `(FROM . TO)', each meaning to replace `FROM' with `TO' when it appears in a directory name. This replacement is done when setting up the default directory of a newly visited file. Every `FROM' string should start with ``^''. Use this feature when you have directories which you normally refer to via absolute symbolic links. Make `TO' the name of the link, and `FROM' the name it is linked to.  File: xemacs.info, Node: Comparing Files, Next: Dired, Prev: ListDir, Up: Files Comparing Files =============== The command `M-x diff' compares two files, displaying the differences in an Emacs buffer named `*Diff*'. It works by running the `diff' program, using options taken from the variable `diff-switches', whose value should be a string. The buffer `*Diff*' has Compilation mode as its major mode, so you can use `C-x `' to visit successive changed locations in the two source files. You can also move to a particular hunk of changes and type `C-c C-c' to find the corresponding source location. You can also use the other special commands of Compilation mode: and for scrolling, and `M-p' and `M-n' for cursor motion. *Note Compilation::. The command `M-x diff-backup' compares a specified file with its most recent backup. If you specify the name of a backup file, `diff-backup' compares it with the source file that it is a backup of. The command `M-x compare-windows' compares the text in the current window with that in the next window. Comparison starts at point in each window. Point moves forward in each window, a character at a time in each window, until the next characters in the two windows are different. Then the command is finished. For more information about windows in Emacs, *Note Windows::. With a numeric argument, `compare-windows' ignores changes in whitespace. If the variable `compare-ignore-case' is non-`nil', it ignores differences in case as well.  File: xemacs.info, Node: Dired, Next: Misc File Ops, Prev: Comparing Files, Up: Files Dired, the Directory Editor =========================== Dired makes it easy to delete or visit many of the files in a single directory at once. It creates an Emacs buffer containing a listing of the directory. You can use the normal Emacs commands to move around in this buffer and special Dired commands to operate on the files. * Menu: * Enter: Dired Enter. How to invoke Dired. * Edit: Dired Edit. Editing the Dired buffer. * Deletion: Dired Deletion. Deleting files with Dired. * Immed: Dired Immed. Other file operations through Dired.  File: xemacs.info, Node: Dired Enter, Next: Dired Edit, Prev: Dired, Up: Dired Entering Dired -------------- To invoke dired, type `C-x d' or `M-x dired'. The command reads a directory name or wildcard file name pattern as a minibuffer argument just like the `list-directory' command, `C-x C-d'. Where `dired' differs from `list-directory' is in naming the buffer after the directory name or the wildcard pattern used for the listing, and putting the buffer into Dired mode so that the special commands of Dired are available in it. The variable `dired-listing-switches' is a string used as an argument to `ls' in making the directory; this string must contain `-l'. To display the Dired buffer in another window rather than in the selected window, use `C-x 4 d' (`dired-other-window)' instead of `C-x d'.  File: xemacs.info, Node: Dired Edit, Next: Dired Deletion, Prev: Dired Enter, Up: Dired Editing in Dired ---------------- Once the Dired buffer exists, you can switch freely between it and other Emacs buffers. Whenever the Dired buffer is selected, certain special commands are provided that operate on files that are listed. The Dired buffer is "read-only", and inserting text in it is not useful, so ordinary printing characters such as `d' and `x' are used for Dired commands. Most Dired commands operate on the file described by the line that point is on. Some commands perform operations immediately; others "flag" a file to be operated on later. Most Dired commands that operate on the current line's file also treat a numeric argument as a repeat count, meaning to act on the files of the next few lines. A negative argument means to operate on the files of the preceding lines, and leave point on the first of those lines. All the usual Emacs cursor motion commands are available in Dired buffers. Some special purpose commands are also provided. The keys `C-n' and `C-p' are redefined so that they try to position the cursor at the beginning of the filename on the line, rather than at the beginning of the line. For extra convenience, and `n' in Dired are equivalent to `C-n'. `p' is equivalent to `C-p'. Moving by lines is done so often in Dired that it deserves to be easy to type. (move up and unflag) is often useful simply for moving up. The `g' command in Dired runs `revert-buffer' to reinitialize the buffer from the actual disk directory and show any changes made in the directory by programs other than Dired. All deletion flags in the Dired buffer are lost when this is done.  File: xemacs.info, Node: Dired Deletion, Next: Dired Immed, Prev: Dired Edit, Up: Dired Deleting Files With Dired ------------------------- The primary use of Dired is to flag files for deletion and then delete them. `d' Flag this file for deletion. `u' Remove deletion-flag on this line. `' Remove deletion-flag on previous line, moving point to that line. `x' Delete the files that are flagged for deletion. `#' Flag all auto-save files (files whose names start and end with `#') for deletion (*note Auto Save::.). `~' Flag all backup files (files whose names end with `~') for deletion (*note Backup::.). `. (Period)' Flag excess numeric backup files for deletion. The oldest and newest few backup files of any one file are exempt; the middle ones are flagged. You can flag a file for deletion by moving to the line describing the file and typing `d' or `C-d'. The deletion flag is visible as a `D' at the beginning of the line. Point is moved to the beginning of the next line, so that repeated `d' commands flag successive files. The files are flagged for deletion rather than deleted immediately to avoid the danger of deleting a file accidentally. Until you direct Dired to delete the flagged files, you can remove deletion flags using the commands `u' and . `u' works just like `d', but removes flags rather than making flags. moves upward, removing flags; it is like `u' with numeric argument automatically negated. To delete the flagged files, type `x'. This command first displays a list of all the file names flagged for deletion, and requests confirmation with `yes'. Once you confirm, all the flagged files are deleted, and their lines are deleted from the text of the Dired buffer. The shortened Dired buffer remains selected. If you answer `no' or quit with `C-g', you return immediately to Dired, with the deletion flags still present and no files actually deleted. The `#', `~', and `.' commands flag many files for deletion, based on their names. These commands are useful precisely because they do not actually delete any files; you can remove the deletion flags from any flagged files that you really wish to keep. `#' flags for deletion all files that appear to have been made by auto-saving (that is, files whose names begin and end with `#'). `~' flags for deletion all files that appear to have been made as backups for files that were edited (that is, files whose names end with `~'). `.' (Period) flags just some of the backup files for deletion: only numeric backups that are not among the oldest few nor the newest few backups of any one file. Normally `dired-kept-versions' (not `kept-new-versions'; that applies only when saving) specifies the number of newest versions of each file to keep, and `kept-old-versions' specifies the number of oldest versions to keep. Period with a positive numeric argument, as in `C-u 3 .', specifies the number of newest versions to keep, overriding `dired-kept-versions'. A negative numeric argument overrides `kept-old-versions', using minus the value of the argument to specify the number of oldest versions of each file to keep.