Manual Pages for UNIX Darwin command on man filename

filename(n) Tcl Built-In Commands filename(n)

NAME

filename - File name conventions supported by Tcl commands

IINNTTRROODDUUCCTTIIOONN All Tcl commands and C procedures that take file names as arguments expect the file names to be in one of three forms, depending on the current platform. On each platform, Tcl supports file names in the standard forms(s) for that platform. In addition, on all platforms,

Tcl supports a Unix-like syntax intended to provide a convenient way of

constructing simple file names. However, scripts that are intended to be portable should not assume a particular form for file names.

Instead, portable scripts must use the ffiillee sspplliitt and ffiillee jjooiinn com-

mands to manipulate file names (see the ffiillee manual entry for more details). PPAATTHH TTYYPPEESS File names are grouped into three general types based on the starting point for the path used to specify the file: absolute, relative, and

volume-relative. Absolute names are completely qualified, giving a

path to the file relative to a particular volume and the root directory on that volume. Relative names are unqualified, giving a path to the

file relative to the current working directory. Volume-relative names

are partially qualified, either giving the path relative to the root directory on the current volume, or relative to the current directory of the specified volume. The ffiillee ppaatthhttyyppee command can be used to determine the type of a given path. PPAATTHH SSYYNNTTAAXX The rules for native names depend on the value reported in the Tcl array element ttccllppllaattffoorrmm((ppllaattffoorrmm)): mmaacc On Apple Macintosh systems, Tcl supports two forms of path

names. The normal Mac style names use colons as path separa-

tors. Paths may be relative or absolute, and file names may contain any character other than colon. A leading colon causes the rest of the path to be interpreted relative to the current directory. If a path contains a colon that is not at the beginning, then the path is interpreted as an absolute path. Sequences of two or more colons anywhere in the path are used to construct relative paths where :::: refers to the parent of the current directory, :::::: refers to the parent of the parent, and so forth. In addition to Macintosh style names, Tcl also supports a

subset of Unix-like names. If a path contains no colons,

then it is interpreted like a Unix path. Slash is used as the path separator. The file name .. refers to the current

directory, and .... refers to the parent of the current direc-

tory. However, some names like // or //.... have no mapping, and are interpreted as Macintosh names. In general, commands that generate file names will return Macintosh style names, but commands that accept file names will take both Macintosh

and Unix-style names.

The following examples illustrate various forms of path names: :: Relative path to the current folder. MMyyFFiillee Relative path to a file named MMyyFFiillee in the current folder. MMyyDDiisskk::MMyyFFiillee Absolute path to a file named MMyyFFiillee on the device named MMyyDDiisskk. ::MMyyDDiirr::MMyyFFiillee Relative path to a file name MMyyFFiillee in a folder named MMyyDDiirr in the current folder. ::::MMyyFFiillee Relative path to a file named MMyyFFiillee in the folder above the current folder. ::::::MMyyFFiillee Relative path to a file named MMyyFFiillee in the folder two levels above the current folder. //MMyyDDiisskk//MMyyFFiillee Absolute path to a file named MMyyFFiillee on the device named MMyyDDiisskk. ....//MMyyFFiillee Relative path to a file named MMyyFFiillee in the folder above the current folder. uunniixx On Unix platforms, Tcl uses path names where the components are separated by slashes. Path names may be relative or absolute, and file names may contain any character other than slash. The file names .. and .... are special and refer to the current directory and the parent of the current directory

respectively. Multiple adjacent slash characters are inter-

preted as a single separator. The following examples illus-

trate various forms of path names: // Absolute path to the root directory. //eettcc//ppaasssswwdd Absolute path to the file named ppaasssswwdd in the directory eettcc in the root directory. .. Relative path to the current directory. ffoooo Relative path to the file ffoooo in the current directory. ffoooo//bbaarr Relative path to the file bbaarr in the directory ffoooo in the current directory. ....//ffoooo Relative path to the file ffoooo in the directory above the current directory.

wwiinnddoowwss On Microsoft Windows platforms, Tcl supports both drive-rela-

tive and UNC style names. Both // and \\ may be used as direc-

tory separators in either type of name. Drive-relative names

consist of an optional drive specifier followed by an abso-

lute or relative path. UNC paths follow the general form \\\\sseerrvveerrnnaammee\\sshhaarreennaammee\\ppaatthh\\ffiillee, but must at the very least

contain the server and share components, i.e. \\\\sseerrvveerr-

nnaammee\\sshhaarreennaammee. In both forms, the file names .. and .... are special and refer to the current directory and the parent of the current directory respectively. The following examples illustrate various forms of path names: \\\\HHoosstt\\sshhaarree//ffiillee Absolute UNC path to a file called ffiillee in the root directory of the export point sshhaarree on the host HHoosstt. Note that repeated use of ffiillee ddiirrnnaammee on this path will give ////HHoosstt//sshhaarree, and will never give just /fB//Host/fR.

cc::ffoooo Volume-relative path to a file ffoooo in the cur-

rent directory on drive cc.

cc:://ffoooo Absolute path to a file ffoooo in the root direc-

tory of drive cc.

ffoooo\\bbaarr Relative path to a file bbaarr in the ffoooo direc-

tory in the current directory on the current volume.

\\ffoooo Volume-relative path to a file ffoooo in the root

directory of the current volume.

\\\\ffoooo Volume-relative path to a file ffoooo in the root

directory of the current volume. This is not a valid UNC path, so the assumption is that the extra backslashes are superfluous. TTIILLDDEE SSUUBBSSTTIITTUUTTIIOONN In addition to the file name rules described above, Tcl also supports

csh-style tilde substitution. If a file name starts with a tilde, then

the file name will be interpreted as if the first element is replaced with the location of the home directory for the given user. If the

tilde is followed immediately by a separator, then the $$HHOOMMEE environ-

ment variable is substituted. Otherwise the characters between the tilde and the next separator are taken as a user name, which is used to retrieve the user's home directory for substitution. The Macintosh and Windows platforms do not support tilde substitution when a user name follows the tilde. On these platforms, attempts to use a tilde followed by a user name will generate an error that the user does not exist when Tcl attempts to interpret that part of the path or otherwise access the file. The behaviour of these paths when not trying to interpret them is the same as on Unix. File names that have a tilde without a user name will be correctly substituted using

the $$HHOOMMEE environment variable, just like for Unix.

PPOORRTTAABBIILLIITTYY IISSSSUUEESS Not all file systems are case sensitive, so scripts should avoid code that depends on the case of characters in a file name. In addition, the character sets allowed on different devices may differ, so scripts should choose file names that do not contain special characters like:

<<>>::""//\\||. The safest approach is to use names consisting of alphanu-

meric characters only. Also Windows 3.1 only supports file names with a root of no more than 8 characters and an extension of no more than 3 characters.

On Windows platforms there are file and path length restrictions. Com-

plete paths or filenames longer than about 260 characters will lead to

errors in most file operations. KKEEYYWWOORRDDSS

current directory, absolute file name, relative file name, volume-rela-

tive file name, portability