rev-parse: --show-cdup

When --show-prefix is useful, sometimes it is easier to cd up to
the toplevel of the tree.  This is equivalent to:

    git rev-parse --show-prefix | sed -e 's|[^/][^/]*|..|g'

but we do not have to invoke sed for that.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 431b8f6..d638bfc 100644 (file)
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -68,10 +68,15 @@ OPTIONS
        Show all refs found in `$GIT_DIR/refs`.
 
 --show-prefix::
-       When the command is invoked from a directory show the
+       When the command is invoked from a subdirectory, show the
        path of the current directory relative to the top-level
        directory.
 
+--show-cdup::
+       When the command is invoked from a subdirectory, show the
+       path of the top-level directory relative to the current
+       directory (typically a sequence of "../", or an empty string).
+
 --since=datestring, --after=datestring::
        Parses the date string, and outputs corresponding
        --max-age= parameter for git-rev-list command.

diff --git a/rev-parse.c b/rev-parse.c
index bb4949a..0c951af 100644 (file)
--- a/rev-parse.c
+++ b/rev-parse.c
@@ -216,6 +216,18 @@ int main(int argc, char **argv)
                                        puts(prefix);
                                continue;
                        }
+                       if (!strcmp(arg, "--show-cdup")) {
+                               const char *pfx = prefix;
+                               while (pfx) {
+                                       pfx = strchr(pfx, '/');
+                                       if (pfx) {
+                                               pfx++;
+                                               printf("../");
+                                       }
+                               }
+                               putchar('\n');
+                               continue;
+                       }
                        if (!strcmp(arg, "--git-dir")) {
                                const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
                                static char cwd[PATH_MAX];