3 # Change the #! line occurring in Python scripts. The new interpreter
4 # pathname must be given with a -i option.
6 # Command line arguments are files or directories to be processed.
7 # Directories are searched recursively for files whose name looks
8 # like a python module.
9 # Symbolic links are always ignored (except as explicit directory
10 # arguments). Of course, the original file is kept as a back-up
11 # (with a "~" attached to its name).
13 # Undoubtedly you can do this using find and sed or perl, but this is
14 # a nice example of Python code that recurses down a directory tree
15 # and uses regular expressions. Also note several subtleties like
16 # preserving the file's mode and avoiding to even write a temp file
17 # when no changes are needed for a file.
19 # NB: by changing only the function fixfile() you can turn this
20 # into a program for a different change to Python programs...
28 err = sys.stderr.write
30 rep = sys.stdout.write
32 new_interpreter = None
35 global new_interpreter
36 usage = ('usage: %s -i /interpreter file-or-directory ...\n' %
39 opts, args = getopt.getopt(sys.argv[1:], 'i:')
40 except getopt.error, msg:
47 if not new_interpreter or new_interpreter[0] != '/' or not args:
48 err('-i option or file-or-directory missing\n')
53 if os.path.isdir(arg):
54 if recursedown(arg): bad = 1
55 elif os.path.islink(arg):
56 err(arg + ': will not process symbolic links\n')
62 ispythonprog = re.compile('^[a-zA-Z0-9_]+\.py$')
64 return ispythonprog.match(name) >= 0
66 def recursedown(dirname):
67 dbg('recursedown(%r)\n' % (dirname,))
70 names = os.listdir(dirname)
72 err('%s: cannot list directory: %r\n' % (dirname, msg))
77 if name in (os.curdir, os.pardir): continue
78 fullname = os.path.join(dirname, name)
79 if os.path.islink(fullname): pass
80 elif os.path.isdir(fullname):
81 subdirs.append(fullname)
83 if fix(fullname): bad = 1
84 for fullname in subdirs:
85 if recursedown(fullname): bad = 1
89 ## dbg('fix(%r)\n' % (filename,))
91 f = open(filename, 'r')
93 err('%s: cannot open: %r\n' % (filename, msg))
98 rep(filename+': no change\n')
101 head, tail = os.path.split(filename)
102 tempname = os.path.join(head, '@' + tail)
104 g = open(tempname, 'w')
107 err('%s: cannot create: %r\n' % (tempname, msg))
109 rep(filename + ': updating\n')
113 buf = f.read(BUFSIZE)
119 # Finishing touch -- move files
121 # First copy the file's mode to the temp file
123 statbuf = os.stat(filename)
124 os.chmod(tempname, statbuf[ST_MODE] & 07777)
125 except os.error, msg:
126 err('%s: warning: chmod failed (%r)\n' % (tempname, msg))
127 # Then make a backup of the original file as filename~
129 os.rename(filename, filename + '~')
130 except os.error, msg:
131 err('%s: warning: backup failed (%r)\n' % (filename, msg))
132 # Now move the temp file to the original file
134 os.rename(tempname, filename)
135 except os.error, msg:
136 err('%s: rename failed (%r)\n' % (filename, msg))
142 if not line.startswith('#!'):
144 if "python" not in line:
146 return '#! %s\n' % new_interpreter
148 if __name__ == '__main__':