Set HTTP user agent to git/GIT_VERSION

[git.git] / Documentation / git-update-index.txt

diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index fdcb8be..0a1b0ad 100644 (file)
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -8,11 +8,14 @@ git-update-index - Modifies the index or directory cache
 
 SYNOPSIS
 --------
 
 SYNOPSIS
 --------

+[verse]

 'git-update-index'
             [--add] [--remove | --force-remove] [--replace] 
             [--refresh [-q] [--unmerged] [--ignore-missing]]
             [--cacheinfo <mode> <object> <file>]\*
             [--chmod=(+|-)x]
 'git-update-index'
             [--add] [--remove | --force-remove] [--replace] 
             [--refresh [-q] [--unmerged] [--ignore-missing]]
             [--cacheinfo <mode> <object> <file>]\*
             [--chmod=(+|-)x]

+            [--assume-unchanged | --no-assume-unchanged]
+            [--really-refresh]

             [--info-only] [--index-info]
             [-z] [--stdin]
             [--verbose]
             [--info-only] [--index-info]
             [-z] [--stdin]
             [--verbose]


@@ -65,6 +68,18 @@ OPTIONS
 --chmod=(+|-)x::
         Set the execute permissions on the updated files.        
 
 --chmod=(+|-)x::
         Set the execute permissions on the updated files.        
 

+--assume-unchanged, --no-assume-unchanged::
+       When these flags are specified, the object name recorded
+       for the paths are not updated.  Instead, these options
+       sets and unsets the "assume unchanged" bit for the
+       paths.  When the "assume unchanged" bit is on, git stops
+       checking the working tree files for possible
+       modifications, so you need to manually unset the bit to
+       tell git when you change the working tree file. This is
+       sometimes helpful when working with a big project on a
+       filesystem that has very slow lstat(2) system call
+       (e.g. cifs).
+

 --info-only::
        Do not create objects in the object database for all
        <file> arguments that follow this flag; just insert
 --info-only::
        Do not create objects in the object database for all
        <file> arguments that follow this flag; just insert


@@ -123,7 +138,9 @@ merging.
 
 To pretend you have a file with mode and sha1 at path, say:
 
 
 To pretend you have a file with mode and sha1 at path, say:
 

-   $ git-update-index --cacheinfo mode sha1 path
+----------------
+$ git-update-index --cacheinfo mode sha1 path
+----------------

 
 '--info-only' is used to register files without placing them in the object
 database.  This is useful for status-only repositories.
 
 '--info-only' is used to register files without placing them in the object
 database.  This is useful for status-only repositories.


@@ -134,11 +151,130 @@ in the database but the file isn't available locally.  '--info-only' is
 useful when the file is available, but you do not wish to update the
 object database.
 
 useful when the file is available, but you do not wish to update the
 object database.
 

+
+Using --index-info
+------------------
+
+`--index-info` is a more powerful mechanism that lets you feed
+multiple entry definitions from the standard input, and designed
+specifically for scripts.  It can take inputs of three formats:
+
+    . mode         SP sha1          TAB path
++
+The first format is what "git-apply --index-info"
+reports, and used to reconstruct a partial tree
+that is used for phony merge base tree when falling
+back on 3-way merge.
+
+    . mode SP type SP sha1          TAB path
++
+The second format is to stuff git-ls-tree output
+into the index file.
+
+    . mode         SP sha1 SP stage TAB path
++
+This format is to put higher order stages into the
+index file and matches git-ls-files --stage output.
+
+To place a higher stage entry to the index, the path should
+first be removed by feeding a mode=0 entry for the path, and
+then feeding necessary input lines in the third format.
+
+For example, starting with this index:
+
+------------
+$ git ls-files -s
+100644 8a1218a1024a212bb3db30becd860315f9f3ac52 0       frotz
+------------
+
+you can feed the following input to `--index-info`:
+
+------------
+$ git update-index --index-info
+0 0000000000000000000000000000000000000000     frotz
+100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1      frotz
+100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2      frotz
+------------
+
+The first line of the input feeds 0 as the mode to remove the
+path; the SHA1 does not matter as long as it is well formatted.
+Then the second and third line feeds stage 1 and stage 2 entries
+for that path.  After the above, we would end up with this:
+
+------------
+$ git ls-files -s
+100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1      frotz
+100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2      frotz
+------------
+
+
+Using "assume unchanged" bit
+----------------------------
+
+Many operations in git depend on your filesystem to have an
+efficient `lstat(2)` implementation, so that `st_mtime`
+information for working tree files can be cheaply checked to see
+if the file contents have changed from the version recorded in
+the index file.  Unfortunately, some filesystems have
+inefficient `lstat(2)`.  If your filesystem is one of them, you
+can set "assume unchanged" bit to paths you have not changed to
+cause git not to do this check.  Note that setting this bit on a
+path does not mean git will check the contents of the file to
+see if it has changed -- it makes git to omit any checking and
+assume it has *not* changed.  When you make changes to working
+tree files, you have to explicitly tell git about it by dropping
+"assume unchanged" bit, either before or after you modify them.
+
+In order to set "assume unchanged" bit, use `--assume-unchanged`
+option.  To unset, use `--no-assume-unchanged`.
+
+The command looks at `core.ignorestat` configuration variable.  When
+this is true, paths updated with `git-update-index paths...` and
+paths updated with other git commands that update both index and
+working tree (e.g. `git-apply --index`, `git-checkout-index -u`,
+and `git-read-tree -u`) are automatically marked as "assume
+unchanged".  Note that "assume unchanged" bit is *not* set if
+`git-update-index --refresh` finds the working tree file matches
+the index (use `git-update-index --really-refresh` if you want
+to mark them as "assume unchanged").
+
+

 Examples
 --------
 To update and refresh only the files already checked out:
 
 Examples
 --------
 To update and refresh only the files already checked out:
 

-   git-checkout-index -n -f -a && git-update-index --ignore-missing --refresh
+----------------
+$ git-checkout-index -n -f -a && git-update-index --ignore-missing --refresh
+----------------
+
+On an inefficient filesystem with `core.ignorestat` set:
+
+------------
+$ git update-index --really-refresh <1>
+$ git update-index --no-assume-unchanged foo.c <2>
+$ git diff --name-only <3>
+$ edit foo.c
+$ git diff --name-only <4>
+M foo.c
+$ git update-index foo.c <5>
+$ git diff --name-only <6>
+$ edit foo.c
+$ git diff --name-only <7>
+$ git update-index --no-assume-unchanged foo.c <8>
+$ git diff --name-only <9>
+M foo.c
+
+<1> forces lstat(2) to set "assume unchanged" bits for paths
+    that match index.
+<2> mark the path to be edited.
+<3> this does lstat(2) and finds index matches the path.
+<4> this does lstat(2) and finds index does not match the path.
+<5> registering the new version to index sets "assume unchanged" bit.
+<6> and it is assumed unchanged.
+<7> even after you edit it.
+<8> you can tell about the change after the fact.
+<9> now it checks with lstat(2) and finds it has been changed.
+------------

 
 
 Configuration
 
 
 Configuration


@@ -146,12 +282,21 @@ Configuration
 
 The command honors `core.filemode` configuration variable.  If
 your repository is on an filesystem whose executable bits are
 
 The command honors `core.filemode` configuration variable.  If
 your repository is on an filesystem whose executable bits are

-unreliable, this should be set to 'false'.  This causes the
-command to ignore differences in file modes recorded in the
-index and the file mode on the filesystem if they differ only on
+unreliable, this should be set to 'false' (see gitlink:git-repo-config[1]).
+This causes the command to ignore differences in file modes recorded
+in the index and the file mode on the filesystem if they differ only on

 executable bit.   On such an unfortunate filesystem, you may
 need to use `git-update-index --chmod=`.
 
 executable bit.   On such an unfortunate filesystem, you may
 need to use `git-update-index --chmod=`.
 

+The command looks at `core.ignorestat` configuration variable.  See
+'Using "assume unchanged" bit' section above.
+
+
+See Also
+--------
+gitlink:git-repo-config[1]
+
+

 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>
 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>