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Added safeguard against failure in __del__.
author Guido van Rossum <guido@python.org>
date Wed, 27 Nov 1996 19:39:58 +0000
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1 \section{Standard Module \sectcode{posixpath}}
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2 \stmodindex{posixpath}
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3
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4 This module implements some useful functions on POSIX pathnames.
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5
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6 \strong{Do not import this module directly.} Instead, import the
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7 module \code{os} and use \code{os.path}.
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8 \stmodindex{os}
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9
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10 \renewcommand{\indexsubitem}{(in module posixpath)}
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11
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12 \begin{funcdesc}{basename}{p}
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13 Return the base name of pathname
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14 \var{p}.
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15 This is the second half of the pair returned by
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16 \code{posixpath.split(\var{p})}.
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17 \end{funcdesc}
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18
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19 \begin{funcdesc}{commonprefix}{list}
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20 Return the longest string that is a prefix of all strings in
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21 \var{list}.
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22 If
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23 \var{list}
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24 is empty, return the empty string (\code{''}).
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25 \end{funcdesc}
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26
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27 \begin{funcdesc}{exists}{p}
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28 Return true if
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29 \var{p}
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30 refers to an existing path.
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31 \end{funcdesc}
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32
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33 \begin{funcdesc}{expanduser}{p}
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34 Return the argument with an initial component of \samp{\~} or
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35 \samp{\~\var{user}} replaced by that \var{user}'s home directory. An
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36 initial \samp{\~{}} is replaced by the environment variable \code{\${}HOME};
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37 an initial \samp{\~\var{user}} is looked up in the password directory through
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38 the built-in module \code{pwd}. If the expansion fails, or if the
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39 path does not begin with a tilde, the path is returned unchanged.
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40 \end{funcdesc}
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41
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42 \begin{funcdesc}{expandvars}{p}
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43 Return the argument with environment variables expanded. Substrings
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44 of the form \samp{\$\var{name}} or \samp{\$\{\var{name}\}} are
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45 replaced by the value of environment variable \var{name}. Malformed
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46 variable names and references to non-existing variables are left
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47 unchanged.
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48 \end{funcdesc}
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49
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50 \begin{funcdesc}{isabs}{p}
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51 Return true if \var{p} is an absolute pathname (begins with a slash).
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52 \end{funcdesc}
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53
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54 \begin{funcdesc}{isfile}{p}
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55 Return true if \var{p} is an existing regular file. This follows
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56 symbolic links, so both \code{islink()} and \code{isfile()} can be true for the same
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57 path.
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58 \end{funcdesc}
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59
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60 \begin{funcdesc}{isdir}{p}
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61 Return true if \var{p} is an existing directory. This follows
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62 symbolic links, so both \code{islink()} and \code{isdir()} can be true for the same
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63 path.
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64 \end{funcdesc}
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65
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66 \begin{funcdesc}{islink}{p}
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67 Return true if
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68 \var{p}
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69 refers to a directory entry that is a symbolic link.
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70 Always false if symbolic links are not supported.
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71 \end{funcdesc}
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72
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73 \begin{funcdesc}{ismount}{p}
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74 Return true if pathname \var{p} is a \dfn{mount point}: a point in a
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75 file system where a different file system has been mounted. The
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76 function checks whether \var{p}'s parent, \file{\var{p}/..}, is on a
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77 different device than \var{p}, or whether \file{\var{p}/..} and
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78 \var{p} point to the same i-node on the same device --- this should
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79 detect mount points for all \UNIX{} and POSIX variants.
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80 \end{funcdesc}
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81
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82 \begin{funcdesc}{join}{p\, q}
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83 Join the paths
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84 \var{p}
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85 and
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86 \var{q} intelligently:
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87 If
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88 \var{q}
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89 is an absolute path, the return value is
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90 \var{q}.
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91 Otherwise, the concatenation of
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92 \var{p}
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93 and
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94 \var{q}
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95 is returned, with a slash (\code{'/'}) inserted unless
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96 \var{p}
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97 is empty or ends in a slash.
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98 \end{funcdesc}
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99
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100 \begin{funcdesc}{normcase}{p}
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101 Normalize the case of a pathname. This returns the path unchanged;
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102 however, a similar function in \code{macpath} converts upper case to
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103 lower case.
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104 \end{funcdesc}
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105
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106 \begin{funcdesc}{samefile}{p\, q}
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107 Return true if both pathname arguments refer to the same file or directory
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108 (as indicated by device number and i-node number).
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109 Raise an exception if a stat call on either pathname fails.
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110 \end{funcdesc}
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111
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112 \begin{funcdesc}{split}{p}
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113 Split the pathname \var{p} in a pair \code{(\var{head}, \var{tail})},
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114 where \var{tail} is the last pathname component and \var{head} is
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115 everything leading up to that. The \var{tail} part will never contain
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116 a slash; if \var{p} ends in a slash, \var{tail} will be empty. If
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117 there is no slash in \var{p}, \var{head} will be empty. If \var{p} is
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118 empty, both \var{head} and \var{tail} are empty. Trailing slashes are
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119 stripped from \var{head} unless it is the root (one or more slashes
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120 only). In nearly all cases, \code{join(\var{head}, \var{tail})}
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121 equals \var{p} (the only exception being when there were multiple
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122 slashes separating \var{head} from \var{tail}).
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123 \end{funcdesc}
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124
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125 \begin{funcdesc}{splitext}{p}
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126 Split the pathname \var{p} in a pair \code{(\var{root}, \var{ext})}
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127 such that \code{\var{root} + \var{ext} == \var{p}},
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128 and \var{ext} is empty or begins with a period and contains
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129 at most one period.
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130 \end{funcdesc}
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131
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132 \begin{funcdesc}{walk}{p\, visit\, arg}
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133 Calls the function \var{visit} with arguments
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134 \code{(\var{arg}, \var{dirname}, \var{names})} for each directory in the
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135 directory tree rooted at \var{p} (including \var{p} itself, if it is a
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136 directory). The argument \var{dirname} specifies the visited directory,
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137 the argument \var{names} lists the files in the directory (gotten from
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138 \code{posix.listdir(\var{dirname})}, so including \samp{.} and
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139 \samp{..}). The \var{visit} function may modify \var{names} to
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140 influence the set of directories visited below \var{dirname}, e.g., to
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141 avoid visiting certain parts of the tree. (The object referred to by
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142 \var{names} must be modified in place, using \code{del} or slice
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143 assignment.)
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144 \end{funcdesc}