This is ../info/xemacs.info, produced by makeinfo version 4.0 from xemacs/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: 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.  File: xemacs.info, Node: Dired Immed, Prev: Dired Deletion, Up: Dired Immediate File Operations in Dired ---------------------------------- Some file operations in Dired take place immediately when they are requested. `C' Copies the file described on the current line. You must supply a file name to copy to, using the minibuffer. `f' Visits the file described on the current line. It is just like typing `C-x C-f' and supplying that file name. If the file on this line is a subdirectory, `f' actually causes Dired to be invoked on that subdirectory. *Note Visiting::. `o' Like `f', but uses another window to display the file's buffer. The Dired buffer remains visible in the first window. This is like using `C-x 4 C-f' to visit the file. *Note Windows::. `R' Renames the file described on the current line. You must supply a file name to rename to, using the minibuffer. `v' Views the file described on this line using `M-x view-file'. Viewing a file is like visiting it, but is slanted toward moving around in the file conveniently and does not allow changing the file. *Note View File: Misc File Ops. Viewing a file that is a directory runs Dired on that directory.  File: xemacs.info, Node: Misc File Ops, Prev: Dired, Up: Files Miscellaneous File Operations ============================= Emacs has commands for performing many other operations on files. All operate on one file; they do not accept wildcard file names. You can use the command `M-x add-name-to-file' to add a name to an existing file without removing the old name. The new name must belong on the file system that the file is on. `M-x append-to-file' adds the text of the region to the end of the specified file. `M-x copy-file' reads the file OLD and writes a new file named NEW with the same contents. Confirmation is required if a file named NEW already exists, because copying overwrites the old contents of the file NEW. `M-x delete-file' deletes a specified file, like the `rm' command in the shell. If you are deleting many files in one directory, it may be more convenient to use Dired (*note Dired::). `M-x insert-file' inserts a copy of the contents of a specified file into the current buffer at point, leaving point unchanged before the contents and the mark after them. *Note Mark::. `M-x make-symbolic-link' reads two file names OLD and LINKNAME, and then creates a symbolic link named LINKNAME and pointing at OLD. Future attempts to open file LINKNAME will then refer to the file named OLD at the time the opening is done, or will result in an error if the name OLD is not in use at that time. Confirmation is required if you create the link while LINKNAME is in use. Note that not all systems support symbolic links. `M-x rename-file' reads two file names OLD and NEW using the minibuffer, then renames file OLD as NEW. If a file named NEW already exists, you must confirm with `yes' or renaming is not done; this is because renaming causes the previous meaning of the name NEW to be lost. If OLD and NEW are on different file systems, the file OLD is copied and deleted. `M-x view-file' allows you to scan or read a file by sequential screenfuls. It reads a file name argument using the minibuffer. After reading the file into an Emacs buffer, `view-file' reads and displays one windowful. You can then type to scroll forward one window, or to scroll backward. Various other commands are provided for moving around in the file, but none for changing it; type `C-h' while viewing a file for a list of them. Most commands are the default Emacs cursor motion commands. To exit from viewing, type `C-c'.  File: xemacs.info, Node: Buffers, Next: Windows, Prev: Files, Up: Top Using Multiple Buffers ********************** Text you are editing in Emacs resides in an object called a "buffer". Each time you visit a file, Emacs creates a buffer to hold the file's text. Each time you invoke Dired, Emacs creates a buffer to hold the directory listing. If you send a message with `C-x m', a buffer named `*mail*' is used to hold the text of the message. When you ask for a command's documentation, it appears in a buffer called `*Help*'. At any time, one and only one buffer is "selected". It is also called the "current buffer". Saying a command operates on "the buffer" really means that the command operates on the selected buffer, as most commands do. When Emacs creates multiple windows, each window has a chosen buffer which is displayed there, but at any time only one of the windows is selected and its chosen buffer is the selected buffer. Each window's mode line displays the name of the buffer the window is displaying (*note Windows::). Each buffer has a name which can be of any length but is case-sensitive. You can select a buffer using its name. Most buffers are created when you visit files; their names are derived from the files' names. You can also create an empty buffer with any name you want. A newly started Emacs has a buffer named `*scratch*' which you can use for evaluating Lisp expressions in Emacs. Each buffer records what file it is visiting, whether it is modified, and what major mode and minor modes are in effect in it (*note Major Modes::). Any Emacs variable can be made "local to" a particular buffer, meaning its value in that buffer can be different from the value in other buffers. *Note Locals::. * Menu: * Select Buffer:: Creating a new buffer or reselecting an old one. * List Buffers:: Getting a list of buffers that exist. * Misc Buffer:: Renaming; changing read-onliness; copying text. * Kill Buffer:: Killing buffers you no longer need. * Several Buffers:: How to go through the list of all buffers and operate variously on several of them.  File: xemacs.info, Node: Select Buffer, Next: List Buffers, Prev: Buffers, Up: Buffers Creating and Selecting Buffers ============================== `C-x b BUFFER ' Select or create a buffer named BUFFER (`switch-to-buffer'). `C-x 4 b BUFFER ' Similar, but select a buffer named BUFFER in another window (`switch-to-buffer-other-window'). `M-x switch-to-other-buffer N' Switch to the previous buffer. To select a buffer named BUFNAME, type `C-x b BUFNAME '. This is the command `switch-to-buffer' with argument BUFNAME. You can use completion on an abbreviation for the buffer name you want (*note Completion::). An empty argument to `C-x b' specifies the most recently selected buffer that is not displayed in any window. Most buffers are created when you visit files, or use Emacs commands that display text. You can also create a buffer explicitly by typing `C-x b BUFNAME ', which creates a new, empty buffer that is not visiting any file, and selects it for editing. The new buffer's major mode is determined by the value of `default-major-mode' (*note Major Modes::). Buffers not visiting files are usually used for making notes to yourself. If you try to save one, you are asked for the file name to use. The function `switch-to-buffer-other-frame' is similar to `switch-to-buffer' except that it creates a new frame in which to display the selected buffer. Use `M-x switch-to-other-buffer' to visit the previous buffer. If you supply a positive integer N, the Nth most recent buffer is displayed. If you supply an argument of 0, the current buffer is moved to the bottom of the buffer stack. Note that you can also use `C-x C-f' and any other command for visiting a file to switch buffers. *Note Visiting::.  File: xemacs.info, Node: List Buffers, Next: Misc Buffer, Prev: Select Buffer, Up: Buffers Listing Existing Buffers ======================== `C-x C-b' List the existing buffers (`list-buffers'). To print a list of all existing buffers, type `C-x C-b'. Each line in the list shows one buffer's name, major mode, and visited file. A `*' at the beginning of a line indicates the buffer has been "modified". If several buffers are modified, it may be time to save some with `C-x s' (*note Saving::). A `%' indicates a read-only buffer. A `.' marks the selected buffer. Here is an example of a buffer list: MR Buffer Size Mode File -- ------ ---- ---- ---- .* emacs.tex 383402 Texinfo /u2/emacs/man/emacs.tex *Help* 1287 Fundamental files.el 23076 Emacs-Lisp /u2/emacs/lisp/files.el % RMAIL 64042 RMAIL /u/rms/RMAIL *% man 747 Dired /u2/emacs/man/ net.emacs 343885 Fundamental /u/rms/net.emacs fileio.c 27691 C /u2/emacs/src/fileio.c NEWS 67340 Text /u2/emacs/etc/NEWS *scratch* 0 Lisp Interaction Note that the buffer `*Help*' was made by a help request; it is not visiting any file. The buffer `man' was made by Dired on the directory `/u2/emacs/man/'. As you move the mouse over the `*Buffer List*' buffer, the lines are highlighted. This visual cue indicates that clicking the right mouse button (`button3') will pop up a menu of commands on the buffer represented by this line. This menu duplicates most of those commands which are bound to keys in the `*Buffer List*' buffer.  File: xemacs.info, Node: Misc Buffer, Next: Kill Buffer, Prev: List Buffers, Up: Buffers Miscellaneous Buffer Operations =============================== `C-x C-q' Toggle read-only status of buffer (`toggle-read-only'). `M-x rename-buffer' Change the name of the current buffer. `M-x view-buffer' Scroll through a buffer. A buffer can be "read-only", which means that commands to change its text are not allowed. Normally, read-only buffers are created by subsystems such as Dired and Rmail that have special commands to operate on the text. Emacs also creates a read-only buffer if you visit a file that is protected. To make changes in a read-only buffer, use the command `C-x C-q' (`toggle-read-only'). It makes a read-only buffer writable, and makes a writable buffer read-only. This works by setting the variable `buffer-read-only', which has a local value in each buffer and makes a buffer read-only if its value is non-`nil'. `M-x rename-buffer' changes the name of the current buffer, prompting for the new name in the minibuffer. There is no default. If you specify a name that is used by a different buffer, an error is signalled and renaming is not done. `M-x view-buffer' is similar to `M-x view-file' (*note Misc File Ops::), but it examines an already existing Emacs buffer. View mode provides convenient commands for scrolling through the buffer but not for changing it. When you exit View mode, the resulting value of point remains in effect. To copy text from one buffer to another, use the commands `M-x append-to-buffer' and `M-x insert-buffer'. *Note Accumulating Text::.  File: xemacs.info, Node: Kill Buffer, Next: Several Buffers, Prev: Misc Buffer, Up: Buffers Killing Buffers =============== After using Emacs for a while, you may accumulate a large number of buffers and may want to eliminate the ones you no longer need. There are several commands for doing this. `C-x k' Kill a buffer, specified by name (`kill-buffer'). `M-x kill-some-buffers' Offer to kill each buffer, one by one. `C-x k' (`kill-buffer') kills one buffer, whose name you specify in the minibuffer. If you type just in the minibuffer, the default, killing the current buffer, is used. If the current buffer is killed, the buffer that has been selected recently but does not appear in any window now is selected. If the buffer being killed contains unsaved changes, you are asked to confirm with `yes' before the buffer is killed. The command `M-x kill-some-buffers' asks about each buffer, one by one. An answer of `y' means to kill the buffer. Killing the current buffer or a buffer containing unsaved changes selects a new buffer or asks for confirmation just like `kill-buffer'.  File: xemacs.info, Node: Several Buffers, Prev: Kill Buffer, Up: Buffers Operating on Several Buffers ============================ The "buffer-menu" facility is like a "Dired for buffers"; it allows you to request operations on various Emacs buffers by editing a buffer containing a list of them. You can save buffers, kill them (here called "deleting" them, for consistency with Dired), or display them. `M-x buffer-menu' Begin editing a buffer listing all Emacs buffers. The command `buffer-menu' writes a list of all Emacs buffers into the buffer `*Buffer List*', and selects that buffer in Buffer Menu mode. The buffer is read-only. You can only change it using the special commands described in this section. Most of the commands are graphic characters. You can use Emacs cursor motion commands in the `*Buffer List*' buffer. If the cursor is on a line describing a buffer, the following special commands apply to that buffer: `d' Request to delete (kill) the buffer, then move down. A `D' before the buffer name on a line indicates a deletion request. Requested deletions actually take place when you use the `x' command. `k' Synonym for `d'. `C-d' Like `d' but move up afterwards instead of down. `s' Request to save the buffer. An `S' before the buffer name on a line indicates the request. Requested saves actually take place when you use the `x' command. You can request both saving and deletion for the same buffer. `~' Mark buffer "unmodified". The command `~' does this immediately when typed. `x' Perform previously requested deletions and saves. `u' Remove any request made for the current line, and move down. `' Move to previous line and remove any request made for that line. All commands that add or remove flags to request later operations also move down a line. They accept a numeric argument as a repeat count, unless otherwise specified. There are also special commands to use the buffer list to select another buffer, and to specify one or more other buffers for display in additional windows. `1' Select the buffer in a full-frame window. This command takes effect immediately. `2' Immediately set up two windows, with this buffer in one and the buffer selected before `*Buffer List*' in the other. `f' Immediately select the buffer in place of the `*Buffer List*' buffer. `o' Immediately select the buffer in another window as if by `C-x 4 b', leaving `*Buffer List*' visible. `q' Immediately select this buffer, and display any buffers previously flagged with the `m' command in other windows. If there are no buffers flagged with `m', this command is equivalent to `1'. `m' Flag this buffer to be displayed in another window if the `q' command is used. The request shows as a `>' at the beginning of the line. The same buffer may not have both a delete request and a display request. Going back between a `buffer-menu' buffer and other Emacs buffers is easy. You can, for example, switch from the `*Buffer List*' buffer to another Emacs buffer, and edit there. You can then reselect the `buffer-menu' buffer and perform operations already requested, or you can kill that buffer or pay no further attention to it. All that `buffer-menu' does directly is create and select a suitable buffer, and turn on Buffer Menu mode. All the other capabilities of the buffer menu are implemented by special commands provided in Buffer Menu mode. The only difference between `buffer-menu' and `list-buffers' is that `buffer-menu' selects the `*Buffer List*' buffer and `list-buffers' does not. If you run `list-buffers' (that is, type `C-x C-b') and select the buffer list manually, you can use all the commands described here.  File: xemacs.info, Node: Windows, Next: Mule, Prev: Buffers, Up: Top Multiple Windows **************** Emacs can split the frame into two or many windows, which can display parts of different buffers or different parts of one buffer. If you are running XEmacs under X, that means you can have the X window that contains the Emacs frame have multiple subwindows. * Menu: * Basic Window:: Introduction to Emacs windows. * Split Window:: New windows are made by splitting existing windows. * Other Window:: Moving to another window or doing something to it. * Pop Up Window:: Finding a file or buffer in another window. * Change Window:: Deleting windows and changing their sizes.  File: xemacs.info, Node: Basic Window, Next: Split Window, Prev: Windows, Up: Windows Concepts of Emacs Windows ========================= When Emacs displays multiple windows, each window has one Emacs buffer designated for display. The same buffer may appear in more than one window; if it does, any changes in its text are displayed in all the windows that display it. Windows showing the same buffer can show different parts of it, because each window has its own value of point. At any time, one window is the "selected window"; the buffer displayed by that window is the current buffer. The cursor shows the location of point in that window. Each other window has a location of point as well, but since the terminal has only one cursor, it cannot show the location of point in the other windows. Commands to move point affect the value of point for the selected Emacs window only. They do not change the value of point in any other Emacs window, including those showing the same buffer. The same is true for commands such as `C-x b' to change the selected buffer in the selected window; they do not affect other windows at all. However, there are other commands such as `C-x 4 b' that select a different window and switch buffers in it. Also, all commands that display information in a window, including (for example) `C-h f' (`describe-function') and `C-x C-b' (`list-buffers'), work by switching buffers in a non-selected window without affecting the selected window. Each window has its own mode line, which displays the buffer name, modification status, and major and minor modes of the buffer that is displayed in the window. *Note Mode Line::, for details on the mode line.  File: xemacs.info, Node: Split Window, Next: Other Window, Prev: Basic Window, Up: Windows Splitting Windows ================= `C-x 2' Split the selected window into two windows, one above the other (`split-window-vertically'). `C-x 3' Split the selected window into two windows positioned side by side (`split-window-horizontally'). `C-x 6' Save the current window configuration in register REG (a letter). `C-x 7' Restore (make current) the window configuration in register REG (a letter). Use with a register previously set with `C-x 6'. The command `C-x 2' (`split-window-vertically') breaks the selected window into two windows, one above the other. Both windows start out displaying the same buffer, with the same value of point. By default each of the two windows gets half the height of the window that was split. A numeric argument specifies how many lines to give to the top window. `C-x 3' (`split-window-horizontally') breaks the selected window into two side-by-side windows. A numeric argument specifies how many columns to give the one on the left. A line of vertical bars separates the two windows. Windows that are not the full width of the frame have truncated mode lines which do not always appear in inverse video, because Emacs display routines cannot display a region of inverse video that is only part of a line on the screen. When a window is less than the full width, many text lines are too long to fit. Continuing all those lines might be confusing. Set the variable `truncate-partial-width-windows' to non-`nil' to force truncation in all windows less than the full width of the frame, independent of the buffer and its value for `truncate-lines'. *Note Continuation Lines::. Horizontal scrolling is often used in side-by-side windows. *Note Display::. You can resize a window and store that configuration in a register by supplying a REGISTER argument to `window-configuration-to-register' (`C-x 6'). To return to the window configuration established with `window-configuration-to-register', use `jump-to-register' (`C-x j').