#!/usr/bin/env python
# Copyright (c) 2002-2005 ActiveState Corp.
# See LICENSE.txt for license details.
# Author:
# Trent Mick (TrentM@ActiveState.com)
# Home:
# http://trentm.com/projects/which/
r"""Find the full path to commands.
which(command, path=None, verbose=0, exts=None)
Return the full path to the first match of the given command on the
path.
whichall(command, path=None, verbose=0, exts=None)
Return a list of full paths to all matches of the given command on
the path.
whichgen(command, path=None, verbose=0, exts=None)
Return a generator which will yield full paths to all matches of the
given command on the path.
By default the PATH environment variable is searched (as well as, on
Windows, the AppPaths key in the registry), but a specific 'path' list
to search may be specified as well. On Windows, the PATHEXT environment
variable is applied as appropriate.
If "verbose" is true then a tuple of the form
(<fullpath>, <matched-where-description>)
is returned for each match. The latter element is a textual description
of where the match was found. For example:
from PATH element 0
from HKLM\SOFTWARE\...\perl.exe
"""
_cmdlnUsage = """
Show the full path of commands.
Usage:
which [<options>...] [<command-name>...]
Options:
-h, --help Print this help and exit.
-V, --version Print the version info and exit.
-a, --all Print *all* matching paths.
-v, --verbose Print out how matches were located and
show near misses on stderr.
-q, --quiet Just print out matches. I.e., do not print out
near misses.
-p <altpath>, --path=<altpath>
An alternative path (list of directories) may
be specified for searching.
-e <exts>, --exts=<exts>
Specify a list of extensions to consider instead
of the usual list (';'-separate list, Windows
only).
Show the full path to the program that would be run for each given
command name, if any. Which, like GNU's which, returns the number of
failed arguments, or -1 when no <command-name> was given.
Near misses include duplicates, non-regular files and (on Un*x)
files without executable access.
"""
__revision__ = "$Id$"
__version_info__ = (1, 1, 0)
__version__ = '.'.join(map(str, __version_info__))
import os
import sys
import getopt
import stat
#---- exceptions
class WhichError(Exception):
pass
#---- internal support stuff
def _getRegisteredExecutable(exeName):
"""Windows allow application paths to be registered in the registry."""
registered = None
if sys.platform.startswith('win'):
if os.path.splitext(exeName)[1].lower() != '.exe':
exeName += '.exe'
import _winreg
try:
key = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\App Paths\\" +\
exeName
value = _winreg.QueryValue(_winreg.HKEY_LOCAL_MACHINE, key)
registered = (value, "from HKLM\\"+key)
except _winreg.error:
pass
if registered and not os.path.exists(registered[0]):
registered = None
return registered
def _samefile(fname1, fname2):
if sys.platform.startswith('win'):
return ( os.path.normpath(os.path.normcase(fname1)) ==\
os.path.normpath(os.path.normcase(fname2)) )
else:
return os.path.samefile(fname1, fname2)
def _cull(potential, matches, verbose=0):
"""Cull inappropriate matches. Possible reasons:
- a duplicate of a previous match
- not a disk file
- not executable (non-Windows)
If 'potential' is approved it is returned and added to 'matches'.
Otherwise, None is returned.
"""
for match in matches: # don't yield duplicates
if _samefile(potential[0], match[0]):
if verbose:
sys.stderr.write("duplicate: %s (%s)\n" % potential)
return None
else:
if not stat.S_ISREG(os.stat(potential[0]).st_mode):
if verbose:
sys.stderr.write("not a regular file: %s (%s)\n" % potential)
elif not os.access(potential[0], os.X_OK):
if verbose:
sys.stderr.write("no executable access: %s (%s)\n"\
% potential)
else:
matches.append(potential)
return potential
#---- module API
def whichgen(command, path=None, verbose=0, exts=None):
"""Return a generator of full paths to the given command.
"command" is a the name of the executable to search for.
"path" is an optional alternate path list to search. The default it
to use the PATH environment variable.
"verbose", if true, will cause a 2-tuple to be returned for each
match. The second element is a textual description of where the
match was found.
"exts" optionally allows one to specify a list of extensions to use
instead of the standard list for this system. This can
effectively be used as an optimization to, for example, avoid
stat's of "foo.vbs" when searching for "foo" and you know it is
not a VisualBasic script but ".vbs" is on PATHEXT. This option
is only supported on Windows.
This method returns a generator which yields either full paths to
the given command or, if verbose, tuples of the form (<path to
command>, <where path found>).
"""
matches = []
if path is None:
usingGivenPath = 0
path = os.environ.get("PATH", "").split(os.pathsep)
if sys.platform.startswith("win"):
path.insert(0, os.curdir) # implied by Windows shell
else:
usingGivenPath = 1
# Windows has the concept of a list of extensions (PATHEXT env var).
if sys.platform.startswith("win"):
if exts is None:
exts = os.environ.get("PATHEXT", "").split(os.pathsep)
# If '.exe' is not in exts then obviously this is Win9x and
# or a bogus PATHEXT, then use a reasonable default.
for ext in exts:
if ext.lower() == ".exe":
break
else:
exts = ['.COM', '.EXE', '.BAT']
elif not isinstance(exts, list):
raise TypeError("'exts' argument must be a list or None")
else:
if exts is not None:
raise WhichError("'exts' argument is not supported on "\
"platform '%s'" % sys.platform)
exts = []
# File name cannot have path separators because PATH lookup does not
# work that way.
if os.sep in command or os.altsep and os.altsep in command:
pass
else:
for i in range(len(path)):
dirName = path[i]
# On windows the dirName *could* be quoted, drop the quotes
if sys.platform.startswith("win") and len(dirName) >= 2\
and dirName[0] == '"' and dirName[-1] == '"':
dirName = dirName[1:-1]
for ext in ['']+exts:
absName = os.path.abspath(
os.path.normpath(os.path.join(dirName, command+ext)))
if os.path.isfile(absName):
if usingGivenPath:
fromWhere = "from given path element %d" % i
elif not sys.platform.startswith("win"):
fromWhere = "from PATH element %d" % i
elif i == 0:
fromWhere = "from current directory"
else:
fromWhere = "from PATH element %d" % (i-1)
match = _cull((absName, fromWhere), matches, verbose)
if match:
if verbose:
yield match
else:
yield match[0]
match = _getRegisteredExecutable(command)
if match is not None:
match = _cull(match, matches, verbose)
if match:
if verbose:
yield match
else:
yield match[0]
def which(command, path=None, verbose=0, exts=None):
"""Return the full path to the first match of the given command on
the path.
"command" is a the name of the executable to search for.
"path" is an optional alternate path list to search. The default it
to use the PATH environment variable.
"verbose", if true, will cause a 2-tuple to be returned. The second
element is a textual description of where the match was found.
"exts" optionally allows one to specify a list of extensions to use
instead of the standard list for this system. This can
effectively be used as an optimization to, for example, avoid
stat's of "foo.vbs" when searching for "foo" and you know it is
not a VisualBasic script but ".vbs" is on PATHEXT. This option
is only supported on Windows.
If no match is found for the command, a WhichError is raised.
"""
try:
match = whichgen(command, path, verbose, exts).next()
except StopIteration:
raise WhichError("Could not find '%s' on the path." % command)
return match
def whichall(command, path=None, verbose=0, exts=None):
"""Return a list of full paths to all matches of the given command
on the path.
"command" is a the name of the executable to search for.
"path" is an optional alternate path list to search. The default it
to use the PATH environment variable.
"verbose", if true, will cause a 2-tuple to be returned for each
match. The second element is a textual description of where the
match was found.
"exts" optionally allows one to specify a list of extensions to use
instead of the standard list for this system. This can
effectively be used as an optimization to, for example, avoid
stat's of "foo.vbs" when searching for "foo" and you know it is
not a VisualBasic script but ".vbs" is on PATHEXT. This option
is only supported on Windows.
"""
return list( whichgen(command, path, verbose, exts) )
#---- mainline
def main(argv):
all = 0
verbose = 0
altpath = None
exts = None
try:
optlist, args = getopt.getopt(argv[1:], 'haVvqp:e:',
['help', 'all', 'version', 'verbose', 'quiet', 'path=', 'exts='])
except getopt.GetoptError, msg:
sys.stderr.write("which: error: %s. Your invocation was: %s\n"\
% (msg, argv))
sys.stderr.write("Try 'which --help'.\n")
return 1
for opt, optarg in optlist:
if opt in ('-h', '--help'):
print _cmdlnUsage
return 0
elif opt in ('-V', '--version'):
print "which %s" % __version__
return 0
elif opt in ('-a', '--all'):
all = 1
elif opt in ('-v', '--verbose'):
verbose = 1
elif opt in ('-q', '--quiet'):
verbose = 0
elif opt in ('-p', '--path'):
if optarg:
altpath = optarg.split(os.pathsep)
else:
altpath = []
elif opt in ('-e', '--exts'):
if optarg:
exts = optarg.split(os.pathsep)
else:
exts = []
if len(args) == 0:
return -1
failures = 0
for arg in args:
#print "debug: search for %r" % arg
nmatches = 0
for match in whichgen(arg, path=altpath, verbose=verbose, exts=exts):
if verbose:
print "%s (%s)" % match
else:
print match
nmatches += 1
if not all:
break
if not nmatches:
failures += 1
return failures
if __name__ == "__main__":
sys.exit( main(sys.argv) )