changeset 45880:d7a508a75d72

strip: move into core As discussed at the 5.2 sprint, replace strip extension by a core command, debugstrip. Obviously, the extension stays for backwards compatibility. As an implementation note, I moved the strip file as is into core, which is not done elsewhere, AFAIK. I could have inlined it into debugcommands, but that doesn't sound great. Differential Revision: https://phab.mercurial-scm.org/D9285
author Valentin Gatien-Baron <valentin.gatienbaron@gmail.com>
date Sun, 08 Nov 2020 16:23:35 -0500
parents 11842aad3195
children 996cd73431a3
files hgext/mq.py hgext/strip.py mercurial/debugcommands.py mercurial/registrar.py mercurial/strip.py relnotes/next tests/test-completion.t tests/test-help.t tests/test-strip.t
diffstat 9 files changed, 311 insertions(+), 286 deletions(-) [+]
line wrap: on
line diff
--- a/hgext/mq.py	Sat Nov 07 16:36:19 2020 -0800
+++ b/hgext/mq.py	Sun Nov 08 16:23:35 2020 -0500
@@ -100,6 +100,7 @@
     revsetlang,
     scmutil,
     smartset,
+    strip,
     subrepoutil,
     util,
     vfs as vfsmod,
@@ -138,7 +139,7 @@
 
 # force load strip extension formerly included in mq and import some utility
 try:
-    stripext = extensions.find(b'strip')
+    extensions.find(b'strip')
 except KeyError:
     # note: load is lazy so we could avoid the try-except,
     # but I (marmoute) prefer this explicit code.
@@ -149,9 +150,9 @@
         def log(self, event, msgfmt, *msgargs, **opts):
             pass
 
-    stripext = extensions.load(dummyui(), b'strip', b'')
-
-strip = stripext.strip
+    extensions.load(dummyui(), b'strip', b'')
+
+strip = strip.strip
 
 
 def checksubstate(repo, baserev=None):
--- a/hgext/strip.py	Sat Nov 07 16:36:19 2020 -0800
+++ b/hgext/strip.py	Sun Nov 08 16:23:35 2020 -0500
@@ -1,287 +1,22 @@
-"""strip changesets and their descendants from history
+"""strip changesets and their descendants from history (DEPRECATED)
+
+The functionality of this extension has been included in core Mercurial
+since version 5.7. Please use :hg:`debugstrip ...` instead.
 
 This extension allows you to strip changesets and all their descendants from the
 repository. See the command help for details.
 """
 from __future__ import absolute_import
 
-from mercurial.i18n import _
-from mercurial.pycompat import getattr
-from mercurial import (
-    bookmarks as bookmarksmod,
-    cmdutil,
-    error,
-    hg,
-    lock as lockmod,
-    mergestate as mergestatemod,
-    node as nodemod,
-    pycompat,
-    registrar,
-    repair,
-    scmutil,
-    util,
-)
+from mercurial import commands
 
-nullid = nodemod.nullid
-release = lockmod.release
-
-cmdtable = {}
-command = registrar.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = b'ships-with-hg-core'
 
-
-def checklocalchanges(repo, force=False):
-    s = repo.status()
-    if not force:
-        cmdutil.checkunfinished(repo)
-        cmdutil.bailifchanged(repo)
-    else:
-        cmdutil.checkunfinished(repo, skipmerge=True)
-    return s
-
-
-def _findupdatetarget(repo, nodes):
-    unode, p2 = repo.changelog.parents(nodes[0])
-    currentbranch = repo[None].branch()
-
-    if (
-        util.safehasattr(repo, b'mq')
-        and p2 != nullid
-        and p2 in [x.node for x in repo.mq.applied]
-    ):
-        unode = p2
-    elif currentbranch != repo[unode].branch():
-        pwdir = b'parents(wdir())'
-        revset = b'max(((parents(%ln::%r) + %r) - %ln::%r) and branch(%s))'
-        branchtarget = repo.revs(
-            revset, nodes, pwdir, pwdir, nodes, pwdir, currentbranch
-        )
-        if branchtarget:
-            cl = repo.changelog
-            unode = cl.node(branchtarget.first())
-
-    return unode
-
-
-def strip(
-    ui,
-    repo,
-    revs,
-    update=True,
-    backup=True,
-    force=None,
-    bookmarks=None,
-    soft=False,
-):
-    with repo.wlock(), repo.lock():
-
-        if update:
-            checklocalchanges(repo, force=force)
-            urev = _findupdatetarget(repo, revs)
-            hg.clean(repo, urev)
-            repo.dirstate.write(repo.currenttransaction())
-
-        if soft:
-            repair.softstrip(ui, repo, revs, backup)
-        else:
-            repair.strip(ui, repo, revs, backup)
-
-        repomarks = repo._bookmarks
-        if bookmarks:
-            with repo.transaction(b'strip') as tr:
-                if repo._activebookmark in bookmarks:
-                    bookmarksmod.deactivate(repo)
-                repomarks.applychanges(repo, tr, [(b, None) for b in bookmarks])
-            for bookmark in sorted(bookmarks):
-                ui.write(_(b"bookmark '%s' deleted\n") % bookmark)
-
-
-@command(
-    b"strip",
-    [
-        (
-            b'r',
-            b'rev',
-            [],
-            _(
-                b'strip specified revision (optional, '
-                b'can specify revisions without this '
-                b'option)'
-            ),
-            _(b'REV'),
-        ),
-        (
-            b'f',
-            b'force',
-            None,
-            _(
-                b'force removal of changesets, discard '
-                b'uncommitted changes (no backup)'
-            ),
-        ),
-        (b'', b'no-backup', None, _(b'do not save backup bundle')),
-        (b'', b'nobackup', None, _(b'do not save backup bundle (DEPRECATED)'),),
-        (b'n', b'', None, _(b'ignored  (DEPRECATED)')),
-        (
-            b'k',
-            b'keep',
-            None,
-            _(b"do not modify working directory during strip"),
-        ),
-        (
-            b'B',
-            b'bookmark',
-            [],
-            _(b"remove revs only reachable from given bookmark"),
-            _(b'BOOKMARK'),
-        ),
-        (
-            b'',
-            b'soft',
-            None,
-            _(b"simply drop changesets from visible history (EXPERIMENTAL)"),
-        ),
-    ],
-    _(b'hg strip [-k] [-f] [-B bookmark] [-r] REV...'),
-    helpcategory=command.CATEGORY_MAINTENANCE,
-)
-def stripcmd(ui, repo, *revs, **opts):
-    """strip changesets and all their descendants from the repository
-
-    The strip command removes the specified changesets and all their
-    descendants. If the working directory has uncommitted changes, the
-    operation is aborted unless the --force flag is supplied, in which
-    case changes will be discarded.
-
-    If a parent of the working directory is stripped, then the working
-    directory will automatically be updated to the most recent
-    available ancestor of the stripped parent after the operation
-    completes.
-
-    Any stripped changesets are stored in ``.hg/strip-backup`` as a
-    bundle (see :hg:`help bundle` and :hg:`help unbundle`). They can
-    be restored by running :hg:`unbundle .hg/strip-backup/BUNDLE`,
-    where BUNDLE is the bundle file created by the strip. Note that
-    the local revision numbers will in general be different after the
-    restore.
-
-    Use the --no-backup option to discard the backup bundle once the
-    operation completes.
-
-    Strip is not a history-rewriting operation and can be used on
-    changesets in the public phase. But if the stripped changesets have
-    been pushed to a remote repository you will likely pull them again.
-
-    Return 0 on success.
-    """
-    opts = pycompat.byteskwargs(opts)
-    backup = True
-    if opts.get(b'no_backup') or opts.get(b'nobackup'):
-        backup = False
-
-    cl = repo.changelog
-    revs = list(revs) + opts.get(b'rev')
-    revs = set(scmutil.revrange(repo, revs))
-
-    with repo.wlock():
-        bookmarks = set(opts.get(b'bookmark'))
-        if bookmarks:
-            repomarks = repo._bookmarks
-            if not bookmarks.issubset(repomarks):
-                raise error.Abort(
-                    _(b"bookmark '%s' not found")
-                    % b','.join(sorted(bookmarks - set(repomarks.keys())))
-                )
-
-            # If the requested bookmark is not the only one pointing to a
-            # a revision we have to only delete the bookmark and not strip
-            # anything. revsets cannot detect that case.
-            nodetobookmarks = {}
-            for mark, node in pycompat.iteritems(repomarks):
-                nodetobookmarks.setdefault(node, []).append(mark)
-            for marks in nodetobookmarks.values():
-                if bookmarks.issuperset(marks):
-                    rsrevs = scmutil.bookmarkrevs(repo, marks[0])
-                    revs.update(set(rsrevs))
-            if not revs:
-                with repo.lock(), repo.transaction(b'bookmark') as tr:
-                    bmchanges = [(b, None) for b in bookmarks]
-                    repomarks.applychanges(repo, tr, bmchanges)
-                for bookmark in sorted(bookmarks):
-                    ui.write(_(b"bookmark '%s' deleted\n") % bookmark)
-
-        if not revs:
-            raise error.Abort(_(b'empty revision set'))
-
-        descendants = set(cl.descendants(revs))
-        strippedrevs = revs.union(descendants)
-        roots = revs.difference(descendants)
-
-        # if one of the wdir parent is stripped we'll need
-        # to update away to an earlier revision
-        update = any(
-            p != nullid and cl.rev(p) in strippedrevs
-            for p in repo.dirstate.parents()
-        )
-
-        rootnodes = {cl.node(r) for r in roots}
-
-        q = getattr(repo, 'mq', None)
-        if q is not None and q.applied:
-            # refresh queue state if we're about to strip
-            # applied patches
-            if cl.rev(repo.lookup(b'qtip')) in strippedrevs:
-                q.applieddirty = True
-                start = 0
-                end = len(q.applied)
-                for i, statusentry in enumerate(q.applied):
-                    if statusentry.node in rootnodes:
-                        # if one of the stripped roots is an applied
-                        # patch, only part of the queue is stripped
-                        start = i
-                        break
-                del q.applied[start:end]
-                q.savedirty()
-
-        revs = sorted(rootnodes)
-        if update and opts.get(b'keep'):
-            urev = _findupdatetarget(repo, revs)
-            uctx = repo[urev]
-
-            # only reset the dirstate for files that would actually change
-            # between the working context and uctx
-            descendantrevs = repo.revs(b"only(., %d)", uctx.rev())
-            changedfiles = []
-            for rev in descendantrevs:
-                # blindly reset the files, regardless of what actually changed
-                changedfiles.extend(repo[rev].files())
-
-            # reset files that only changed in the dirstate too
-            dirstate = repo.dirstate
-            dirchanges = [f for f in dirstate if dirstate[f] != b'n']
-            changedfiles.extend(dirchanges)
-
-            repo.dirstate.rebuild(urev, uctx.manifest(), changedfiles)
-            repo.dirstate.write(repo.currenttransaction())
-
-            # clear resolve state
-            mergestatemod.mergestate.clean(repo)
-
-            update = False
-
-        strip(
-            ui,
-            repo,
-            revs,
-            backup=backup,
-            update=update,
-            force=opts.get(b'force'),
-            bookmarks=bookmarks,
-            soft=opts[b'soft'],
-        )
-
-    return 0
+# This is a bit ugly, but a uisetup function that defines strip as an
+# alias for debugstrip would override any user alias for strip,
+# including aliases like "strip = strip --no-backup".
+commands.command.rename(old=b'debugstrip', new=b'debugstrip|strip')
--- a/mercurial/debugcommands.py	Sat Nov 07 16:36:19 2020 -0800
+++ b/mercurial/debugcommands.py	Sun Nov 08 16:23:35 2020 -0500
@@ -78,6 +78,7 @@
     sshpeer,
     sslutil,
     streamclone,
+    strip,
     tags as tagsmod,
     templater,
     treediscovery,
@@ -105,7 +106,9 @@
 
 release = lockmod.release
 
-command = registrar.command()
+table = {}
+table.update(strip.command._table)
+command = registrar.command(table)
 
 
 @command(b'debugancestor', [], _(b'[INDEX] REV1 REV2'), optionalrepo=True)
--- a/mercurial/registrar.py	Sat Nov 07 16:36:19 2020 -0800
+++ b/mercurial/registrar.py	Sun Nov 08 16:23:35 2020 -0500
@@ -234,6 +234,12 @@
             self._table[name] = func, list(options)
         return func
 
+    def rename(self, old, new):
+        """rename a command. Used to add aliases, debugstrip ->
+        debugstrip|strip
+        """
+        self._table[new] = self._table.pop(old)
+
 
 INTENT_READONLY = b'readonly'
 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/strip.py	Sun Nov 08 16:23:35 2020 -0500
@@ -0,0 +1,277 @@
+from __future__ import absolute_import
+
+from .i18n import _
+from .pycompat import getattr
+from . import (
+    bookmarks as bookmarksmod,
+    cmdutil,
+    error,
+    hg,
+    lock as lockmod,
+    mergestate as mergestatemod,
+    node as nodemod,
+    pycompat,
+    registrar,
+    repair,
+    scmutil,
+    util,
+)
+
+nullid = nodemod.nullid
+release = lockmod.release
+
+cmdtable = {}
+command = registrar.command(cmdtable)
+
+
+def checklocalchanges(repo, force=False):
+    s = repo.status()
+    if not force:
+        cmdutil.checkunfinished(repo)
+        cmdutil.bailifchanged(repo)
+    else:
+        cmdutil.checkunfinished(repo, skipmerge=True)
+    return s
+
+
+def _findupdatetarget(repo, nodes):
+    unode, p2 = repo.changelog.parents(nodes[0])
+    currentbranch = repo[None].branch()
+
+    if (
+        util.safehasattr(repo, b'mq')
+        and p2 != nullid
+        and p2 in [x.node for x in repo.mq.applied]
+    ):
+        unode = p2
+    elif currentbranch != repo[unode].branch():
+        pwdir = b'parents(wdir())'
+        revset = b'max(((parents(%ln::%r) + %r) - %ln::%r) and branch(%s))'
+        branchtarget = repo.revs(
+            revset, nodes, pwdir, pwdir, nodes, pwdir, currentbranch
+        )
+        if branchtarget:
+            cl = repo.changelog
+            unode = cl.node(branchtarget.first())
+
+    return unode
+
+
+def strip(
+    ui,
+    repo,
+    revs,
+    update=True,
+    backup=True,
+    force=None,
+    bookmarks=None,
+    soft=False,
+):
+    with repo.wlock(), repo.lock():
+
+        if update:
+            checklocalchanges(repo, force=force)
+            urev = _findupdatetarget(repo, revs)
+            hg.clean(repo, urev)
+            repo.dirstate.write(repo.currenttransaction())
+
+        if soft:
+            repair.softstrip(ui, repo, revs, backup)
+        else:
+            repair.strip(ui, repo, revs, backup)
+
+        repomarks = repo._bookmarks
+        if bookmarks:
+            with repo.transaction(b'strip') as tr:
+                if repo._activebookmark in bookmarks:
+                    bookmarksmod.deactivate(repo)
+                repomarks.applychanges(repo, tr, [(b, None) for b in bookmarks])
+            for bookmark in sorted(bookmarks):
+                ui.write(_(b"bookmark '%s' deleted\n") % bookmark)
+
+
+@command(
+    b"debugstrip",
+    [
+        (
+            b'r',
+            b'rev',
+            [],
+            _(
+                b'strip specified revision (optional, '
+                b'can specify revisions without this '
+                b'option)'
+            ),
+            _(b'REV'),
+        ),
+        (
+            b'f',
+            b'force',
+            None,
+            _(
+                b'force removal of changesets, discard '
+                b'uncommitted changes (no backup)'
+            ),
+        ),
+        (b'', b'no-backup', None, _(b'do not save backup bundle')),
+        (b'', b'nobackup', None, _(b'do not save backup bundle (DEPRECATED)'),),
+        (b'n', b'', None, _(b'ignored  (DEPRECATED)')),
+        (
+            b'k',
+            b'keep',
+            None,
+            _(b"do not modify working directory during strip"),
+        ),
+        (
+            b'B',
+            b'bookmark',
+            [],
+            _(b"remove revs only reachable from given bookmark"),
+            _(b'BOOKMARK'),
+        ),
+        (
+            b'',
+            b'soft',
+            None,
+            _(b"simply drop changesets from visible history (EXPERIMENTAL)"),
+        ),
+    ],
+    _(b'hg debugstrip [-k] [-f] [-B bookmark] [-r] REV...'),
+    helpcategory=command.CATEGORY_MAINTENANCE,
+)
+def debugstrip(ui, repo, *revs, **opts):
+    """strip changesets and all their descendants from the repository
+
+    The strip command removes the specified changesets and all their
+    descendants. If the working directory has uncommitted changes, the
+    operation is aborted unless the --force flag is supplied, in which
+    case changes will be discarded.
+
+    If a parent of the working directory is stripped, then the working
+    directory will automatically be updated to the most recent
+    available ancestor of the stripped parent after the operation
+    completes.
+
+    Any stripped changesets are stored in ``.hg/strip-backup`` as a
+    bundle (see :hg:`help bundle` and :hg:`help unbundle`). They can
+    be restored by running :hg:`unbundle .hg/strip-backup/BUNDLE`,
+    where BUNDLE is the bundle file created by the strip. Note that
+    the local revision numbers will in general be different after the
+    restore.
+
+    Use the --no-backup option to discard the backup bundle once the
+    operation completes.
+
+    Strip is not a history-rewriting operation and can be used on
+    changesets in the public phase. But if the stripped changesets have
+    been pushed to a remote repository you will likely pull them again.
+
+    Return 0 on success.
+    """
+    opts = pycompat.byteskwargs(opts)
+    backup = True
+    if opts.get(b'no_backup') or opts.get(b'nobackup'):
+        backup = False
+
+    cl = repo.changelog
+    revs = list(revs) + opts.get(b'rev')
+    revs = set(scmutil.revrange(repo, revs))
+
+    with repo.wlock():
+        bookmarks = set(opts.get(b'bookmark'))
+        if bookmarks:
+            repomarks = repo._bookmarks
+            if not bookmarks.issubset(repomarks):
+                raise error.Abort(
+                    _(b"bookmark '%s' not found")
+                    % b','.join(sorted(bookmarks - set(repomarks.keys())))
+                )
+
+            # If the requested bookmark is not the only one pointing to a
+            # a revision we have to only delete the bookmark and not strip
+            # anything. revsets cannot detect that case.
+            nodetobookmarks = {}
+            for mark, node in pycompat.iteritems(repomarks):
+                nodetobookmarks.setdefault(node, []).append(mark)
+            for marks in nodetobookmarks.values():
+                if bookmarks.issuperset(marks):
+                    rsrevs = scmutil.bookmarkrevs(repo, marks[0])
+                    revs.update(set(rsrevs))
+            if not revs:
+                with repo.lock(), repo.transaction(b'bookmark') as tr:
+                    bmchanges = [(b, None) for b in bookmarks]
+                    repomarks.applychanges(repo, tr, bmchanges)
+                for bookmark in sorted(bookmarks):
+                    ui.write(_(b"bookmark '%s' deleted\n") % bookmark)
+
+        if not revs:
+            raise error.Abort(_(b'empty revision set'))
+
+        descendants = set(cl.descendants(revs))
+        strippedrevs = revs.union(descendants)
+        roots = revs.difference(descendants)
+
+        # if one of the wdir parent is stripped we'll need
+        # to update away to an earlier revision
+        update = any(
+            p != nullid and cl.rev(p) in strippedrevs
+            for p in repo.dirstate.parents()
+        )
+
+        rootnodes = {cl.node(r) for r in roots}
+
+        q = getattr(repo, 'mq', None)
+        if q is not None and q.applied:
+            # refresh queue state if we're about to strip
+            # applied patches
+            if cl.rev(repo.lookup(b'qtip')) in strippedrevs:
+                q.applieddirty = True
+                start = 0
+                end = len(q.applied)
+                for i, statusentry in enumerate(q.applied):
+                    if statusentry.node in rootnodes:
+                        # if one of the stripped roots is an applied
+                        # patch, only part of the queue is stripped
+                        start = i
+                        break
+                del q.applied[start:end]
+                q.savedirty()
+
+        revs = sorted(rootnodes)
+        if update and opts.get(b'keep'):
+            urev = _findupdatetarget(repo, revs)
+            uctx = repo[urev]
+
+            # only reset the dirstate for files that would actually change
+            # between the working context and uctx
+            descendantrevs = repo.revs(b"only(., %d)", uctx.rev())
+            changedfiles = []
+            for rev in descendantrevs:
+                # blindly reset the files, regardless of what actually changed
+                changedfiles.extend(repo[rev].files())
+
+            # reset files that only changed in the dirstate too
+            dirstate = repo.dirstate
+            dirchanges = [f for f in dirstate if dirstate[f] != b'n']
+            changedfiles.extend(dirchanges)
+
+            repo.dirstate.rebuild(urev, uctx.manifest(), changedfiles)
+            repo.dirstate.write(repo.currenttransaction())
+
+            # clear resolve state
+            mergestatemod.mergestate.clean(repo)
+
+            update = False
+
+        strip(
+            ui,
+            repo,
+            revs,
+            backup=backup,
+            update=update,
+            force=opts.get(b'force'),
+            bookmarks=bookmarks,
+            soft=opts[b'soft'],
+        )
+
+    return 0
--- a/relnotes/next	Sat Nov 07 16:36:19 2020 -0800
+++ b/relnotes/next	Sun Nov 08 16:23:35 2020 -0500
@@ -2,6 +2,9 @@
 
 
 
+ * `hg strip`, from the strip extension, is now a core command, `hg
+   debugstrip`. The extension remains for compatibility.
+
 == New Experimental Features ==
 
 
--- a/tests/test-completion.t	Sat Nov 07 16:36:19 2020 -0800
+++ b/tests/test-completion.t	Sun Nov 08 16:23:35 2020 -0500
@@ -131,6 +131,7 @@
   debugsetparents
   debugsidedata
   debugssl
+  debugstrip
   debugsub
   debugsuccessorssets
   debugtagscache
@@ -319,6 +320,7 @@
   debugsetparents: 
   debugsidedata: changelog, manifest, dir
   debugssl: 
+  debugstrip: rev, force, no-backup, nobackup, , keep, bookmark, soft
   debugsub: rev
   debugsuccessorssets: closest
   debugtagscache: 
--- a/tests/test-help.t	Sat Nov 07 16:36:19 2020 -0800
+++ b/tests/test-help.t	Sun Nov 08 16:23:35 2020 -0500
@@ -380,7 +380,6 @@
        relink        recreates hardlinks between repository clones
        schemes       extend schemes with shortcuts to repository swarms
        share         share a common history between several working directories
-       strip         strip changesets and their descendants from history
        transplant    command to transplant changesets from another branch
        win32mbcs     allow the use of MBCS paths with problematic encodings
        zeroconf      discover and advertise repositories on the local network
@@ -1067,6 +1066,7 @@
    debugsidedata
                  dump the side data for a cl/manifest/file revision
    debugssl      test a secure connection to a server
+   debugstrip    strip changesets and all their descendants from the repository
    debugsub      (no help text available)
    debugsuccessorssets
                  show set of successors for revision
--- a/tests/test-strip.t	Sat Nov 07 16:36:19 2020 -0800
+++ b/tests/test-strip.t	Sun Nov 08 16:23:35 2020 -0500
@@ -10,7 +10,7 @@
   >     hg up -C $1
   >     echo % before update $1, strip $2
   >     hg log -G -T '{rev}:{node}'
-  >     hg --traceback strip $2
+  >     hg --traceback debugstrip $2
   >     echo % after update $1, strip $2
   >     hg log -G -T '{rev}:{node}'
   >     restore
@@ -765,13 +765,11 @@
 Make sure no one adds back a -b option:
 
   $ hg strip -b tip
-  hg strip: option -b not recognized
-  hg strip [-k] [-f] [-B bookmark] [-r] REV...
+  hg debugstrip: option -b not recognized
+  hg debugstrip [-k] [-f] [-B bookmark] [-r] REV...
   
   strip changesets and all their descendants from the repository
   
-  (use 'hg help -e strip' to show help for the strip extension)
-  
   options ([+] can be repeated):
   
    -r --rev REV [+]           strip specified revision (optional, can specify
@@ -783,7 +781,7 @@
    -B --bookmark BOOKMARK [+] remove revs only reachable from given bookmark
       --mq                    operate on patch repository
   
-  (use 'hg strip -h' to show more help)
+  (use 'hg debugstrip -h' to show more help)
   [255]
 
   $ cd ..