Ubuntu Manpage: fileutil - Procedures implementing some file utilities

NAME

       fileutil - Procedures implementing some file utilities

SYNOPSIS

       package require Tcl  8

       package require fileutil  ?1.16.1?

       ::fileutil::lexnormalize path

       ::fileutil::fullnormalize path

       ::fileutil::test path codes ?msgvar? ?label?

       ::fileutil::cat (?options? file)...

       ::fileutil::writeFile ?options? file data

       ::fileutil::appendToFile ?options? file data

       ::fileutil::insertIntoFile ?options? file at data

       ::fileutil::removeFromFile ?options? file at n

       ::fileutil::replaceInFile ?options? file at n data

       ::fileutil::updateInPlace ?options? file cmd

       ::fileutil::fileType filename

       ::fileutil::find ?basedir ?filtercmd??

       ::fileutil::findByPattern basedir ?-regexp|-glob? ?--? patterns

       ::fileutil::foreachLine var filename cmd

       ::fileutil::grep pattern ?files?

       ::fileutil::install ?-m mode? source destination

       ::fileutil::stripN path n

       ::fileutil::stripPwd path

       ::fileutil::stripPath prefix path

       ::fileutil::jail jail path

       ::fileutil::touch ?-a? ?-c? ?-m? ?-r ref_file? ?-t time? filename ?...?

       ::fileutil::tempdir

       ::fileutil::tempdir path

       ::fileutil::tempdirReset

       ::fileutil::tempfile ?prefix?

       ::fileutil::maketempdir ?-prefix str? ?-suffix str? ?-dir str?

       ::fileutil::relative base dst

       ::fileutil::relativeUrl base dst

_________________________________________________________________________________________________

DESCRIPTION

This package provides implementations of standard unix utilities.

::fileutil::lexnormalize path
This command performs purely lexical normalization on the path and returns the
changed path as its result. Symbolic links in the path are not resolved.

Examples:

fileutil::lexnormalize /foo/./bar
=> /foo/bar

fileutil::lexnormalize /foo/../bar
=> /bar

::fileutil::fullnormalize path
This command resolves all symbolic links in the path and returns the changed path
as its result. In contrast to the builtin file normalize this command resolves a
symbolic link in the last element of the path as well.

::fileutil::test path codes ?msgvar? ?label?
A command for the testing of several properties of a path. The properties to test
for are specified in codes, either as a list of keywords describing the properties,
or as a string where each letter is a shorthand for a property to test. The
recognized keywords, shorthands, and associated properties are shown in the list
below. The tests are executed in the order given to the command.

The result of the command is a boolean value. It will be true if and only if the
path passes all the specified tests. In the case of the path not passing one or
more test the first failing test will leave a message in the variable referenced by
msgvar, if such is specified. The message will be prefixed with label, if it is
specified. Note that the variabled referenced by msgvar is not touched at all if
all the tests pass.

read file readable

write file writable

exists file exists

exec file executable

file file isfile

dir file isdirectory

::fileutil::cat (?options? file)...
A tcl implementation of the UNIX cat command. Returns the contents of the
specified file(s). The arguments are files to read, with interspersed options
configuring the process. If there are problems reading any of the files, an error
will occur, and no data will be returned.

The options accepted are -encoding, -translation, -eofchar, and --. With the
exception of the last all options take a single value as argument, as specified by
the tcl builtin command fconfigure. The -- has to be used to terminate option
processing before a file if that file's name begins with a dash.

Each file can have its own set of options coming before it, and for anything not
specified directly the defaults are inherited from the options of the previous
file. The first file inherits the system default for unspecified options.

::fileutil::writeFile ?options? file data
The command replaces the current contents of the specified file with data, with the
process configured by the options. The command accepts the same options as
::fileutil::cat. The specification of a non-existent file is legal and causes the
command to create the file (and all required but missing directories).

::fileutil::appendToFile ?options? file data
This command is like ::fileutil::writeFile, except that the previous contents of
file are not replaced, but appended to. The command accepts the same options as
::fileutil::cat

::fileutil::insertIntoFile ?options? file at data
This comment is similar to ::fileutil::appendToFile, except that the new data is
not appended at the end, but inserted at a specified location within the file. In
further contrast this command has to be given the path to an existing file. It will
not create a missing file, but throw an error instead.

The specified location at has to be an integer number in the range 0 ... [file size
file]. 0 will cause insertion of the new data before the first character of the
existing content, whereas [file size file] causes insertion after the last
character of the existing content, i.e. appending.

The command accepts the same options as ::fileutil::cat.

::fileutil::removeFromFile ?options? file at n
This command is the complement to ::fileutil::insertIntoFile, removing n characters
from the file, starting at location at. The specified location at has to be an
integer number in the range 0 ... [file size file] - n. 0 will cause the removal of
the new data to start with the first character of the existing content, whereas
[file size file] - n causes the removal of the tail of the existing content, i.e.
the truncation of the file.

The command accepts the same options as ::fileutil::cat.

::fileutil::replaceInFile ?options? file at n data
This command is a combination of ::fileutil::removeFromFile and
::fileutil::insertIntoFile. It first removes the part of the contents specified by
the arguments at and n, and then inserts data at the given location, effectively
replacing the removed by content with data. All constraints imposed on at and n by
::fileutil::removeFromFile and ::fileutil::insertIntoFile are obeyed.

The command accepts the same options as ::fileutil::cat.

::fileutil::updateInPlace ?options? file cmd
This command can be seen as the generic core functionality of
::fileutil::replaceInFile. It first reads the contents of the specified file, then
runs the command prefix cmd with that data appended to it, and at last writes the
result of that invokation back as the new contents of the file.

If the executed command throws an error the file is not changed.

The command accepts the same options as ::fileutil::cat.

::fileutil::fileType filename
An implementation of the UNIX file command, which uses various heuristics to guess
the type of a file. Returns a list specifying as much type information as can be
determined about the file, from most general (eg, "binary" or "text") to most
specific (eg, "gif"). For example, the return value for a GIF file would be
"binary graphic gif". The command will detect the following types of files:
directory, empty, binary, text, script (with interpreter), executable elf,
executable dos, executable ne, executable pe, graphic gif, graphic jpeg, graphic
png, graphic tiff, graphic bitmap, html, xml (with doctype if available), message
pgp, binary pdf, text ps, text eps, binary gravity_wave_data_frame, compressed
bzip, compressed gzip, compressed zip, compressed tar, audio wave, audio mpeg, and
link. It further detects doctools, doctoc, and docidx documentation files, and
tklib diagrams.

::fileutil::find ?basedir ?filtercmd??
An implementation of the unix command find. Adapted from the Tcler's Wiki. Takes at
most two arguments, the path to the directory to start searching from and a command
to use to evaluate interest in each file. The path defaults to ".", i.e. the
current directory. The command defaults to the empty string, which means that all
files are of interest. The command takes care not to lose itself in infinite loops
upon encountering circular link structures. The result of the command is a list
containing the paths to the interesting files.

The filtercmd, if specified, is interpreted as a command prefix and one argument is
added to it, the name of the file or directory find is currently looking at. Note
that this name is not fully qualified. It has to be joined it with the result of
pwd to get an absolute filename.

The result of filtercmd is a boolean value that indicates if the current file
should be included in the list of interesting files.

Example:

# find .tcl files
package require fileutil
proc is_tcl {name} {return [string match *.tcl $name]}
set tcl_files [fileutil::find . is_tcl]

::fileutil::findByPattern basedir ?-regexp|-glob? ?--? patterns
This command is based upon the TclX command recursive_glob, except that it doesn't
allow recursion over more than one directory at a time. It uses ::fileutil::find
internally and is thus able to and does follow symbolic links, something the TclX
command does not do. First argument is the directory to start the search in, second
argument is a list of patterns. The command returns a list of all files reachable
through basedir whose names match at least one of the patterns. The options before
the pattern-list determine the style of matching, either regexp or glob. glob-style
matching is the default if no options are given. Usage of the option -- stops
option processing. This allows the use of a leading '-' in the patterns.

::fileutil::foreachLine var filename cmd
The command reads the file filename and executes the script cmd for every line in
the file. During the execution of the script the variable var is set to the
contents of the current line. The return value of this command is the result of the
last invocation of the script cmd or the empty string if the file was empty.

::fileutil::grep pattern ?files?
Implementation of grep. Adapted from the Tcler's Wiki. The first argument defines
the pattern to search for. This is followed by a list of files to search through.
The list is optional and stdin will be used if it is missing. The result of the
procedures is a list containing the matches. Each match is a single element of the
list and contains filename, number and contents of the matching line, separated by
a colons.

::fileutil::install ?-m mode? source destination
The install command is similar in functionality to the install command found on
many unix systems, or the shell script distributed with many source distributions
(unix/install-sh in the Tcl sources, for example). It copies source, which can be
either a file or directory to destination, which should be a directory, unless
source is also a single file. The ?-m? option lets the user specify a unix-style
mode (either octal or symbolic - see file attributes.

::fileutil::stripN path n
Removes the first n elements from the specified path and returns the modified path.
If n is greater than the number of components in path an empty string is returned.
The number of components in a given path may be determined by performing llength on
the list returned by file split.

::fileutil::stripPwd path
If, and only if the path is inside of the directory returned by [pwd] (or the
current working directory itself) it is made relative to that directory. In other
words, the current working directory is stripped from the path. The possibly
modified path is returned as the result of the command. If the current working
directory itself was specified for path the result is the string ".".

::fileutil::stripPath prefix path
If, and only of the path is inside of the directory "prefix" (or the prefix
directory itself) it is made relative to that directory. In other words, the prefix
directory is stripped from the path. The possibly modified path is returned as the
result of the command. If the prefix directory itself was specified for path the
result is the string ".".

::fileutil::jail jail path
This command ensures that the path is not escaping the directory jail. It always
returns an absolute path derived from path which is within jail.

If path is an absolute path and already within jail it is returned unmodified.

An absolute path outside of jail is stripped of its root element and then put into
the jail by prefixing it with it. The same happens if path is relative, except that
nothing is stripped of it. Before adding the jail prefix the path is lexically
normalized to prevent the caller from using .. segments in path to escape the jail.

::fileutil::touch ?-a? ?-c? ?-m? ?-r ref_file? ?-t time? filename ?...?
Implementation of touch. Alter the atime and mtime of the specified files. If -c,
do not create files if they do not already exist. If -r, use the atime and mtime
from ref_file. If -t, use the integer clock value time. It is illegal to specify
both -r and -t. If -a, only change the atime. If -m, only change the mtime.

This command is not available for Tcl versions less than 8.3.

::fileutil::tempdir
The command returns the path of a directory where the caller can place temporary
files, such as "/tmp" on Unix systems. The algorithm we use to find the correct
directory is as follows:

[1] The directory set by an invokation of ::fileutil::tempdir with an argument.
If this is present it is tried exclusively and none of the following item
are tried.

[2] The directory named in the TMPDIR environment variable.

[3] The directory named in the TEMP environment variable.

[4] The directory named in the TMP environment variable.

[5] A platform specific location:

Windows
"C:\TEMP", "C:\TMP", "\TEMP", and "\TMP" are tried in that order.

(classic) Macintosh
The TRASH_FOLDER environment variable is used. This is most likely
not correct.

Unix The directories "/tmp", "/var/tmp", and "/usr/tmp" are tried in that
order.

The algorithm utilized is mainly that used in the Python standard library. The exception
is the first item, the ability to have the search overridden by a user-specified
directory.

::fileutil::tempdir path
In this mode the command sets the path as the first and only directory to try as a
temp. directory. See the previous item for the use of the set directory. The
command returns the empty string.

::fileutil::tempdirReset
Invoking this command clears the information set by the last call of
[::fileutil::tempdir path]. See the last item too.

::fileutil::tempfile ?prefix?
The command generates a temporary file name suitable for writing to, and the
associated file. The file name will be unique, and the file will be writable and
contained in the appropriate system specific temp directory. The name of the file
will be returned as the result of the command.

The code was taken from http://wiki.tcl.tk/772, attributed to Igor Volobouev and
anon.

::fileutil::maketempdir ?-prefix str? ?-suffix str? ?-dir str?
The command generates a temporary directory suitable for writing to. The directory
name will be unique, and the directory will be writable and contained in the
appropriate system specific temp directory. The name of the directory will be
returned as the result of the command.

The three options can used to tweak the behaviour of the command:

-prefix str
The initial, fixed part of the directory name. Defaults to tmp if not
specified.

-suffix str
The fixed tail of the directory. Defaults to the empty string if not
specified.

-dir str
The directory to place the new directory into. Defaults to the result of
fileutil::tempdir if not specified.

The initial code for this was supplied by Miguel Martinez Lopez
[mailto:aplicacionamedida@gmail.com].

::fileutil::relative base dst
This command takes two directory paths, both either absolute or relative and
computes the path of dst relative to base. This relative path is returned as the
result of the command. As implied in the previous sentence, the command is not able
to compute this relationship between the arguments if one of the paths is absolute
and the other relative.

Note: The processing done by this command is purely lexical. Symbolic links are
not taken into account.

::fileutil::relativeUrl base dst
This command takes two file paths, both either absolute or relative and computes
the path of dst relative to base, as seen from inside of the base. This is the
algorithm how a browser resolves a relative link found in the currently shown file.

The computed relative path is returned as the result of the command. As implied in
the previous sentence, the command is not able to compute this relationship between
the arguments if one of the paths is absolute and the other relative.

Note: The processing done by this command is purely lexical. Symbolic links are
not taken into account.

WARNINGS AND INCOMPATIBILITIES

       1.14.9 In this version fileutil::find's broken system for handling symlinks  was  replaced
              with  one working correctly and properly enumerating all the legal non-cyclic paths
              under a base directory.

              While correct this means  that  certain  pathological  directory  hierarchies  with
              cross-linked  sym-links  will  now take about O(n**2) time to enumerate whereas the
              original broken code managed O(3tcl) due to its brokenness.

              A concrete example and extreme case is the "/sys" hierarchy under Linux where  some
              hundred  devices exist under both "/sys/devices" and "/sys/class" with the two sub-
              hierarchies linking to the other, generating millions of legal paths to  enumerate.
              The structure, reduced to three devices, roughly looks like

                /sys/class/tty/tty0 --> ../../dev/tty0
                /sys/class/tty/tty1 --> ../../dev/tty1
                /sys/class/tty/tty2 --> ../../dev/tty1

                /sys/dev/tty0/bus
                /sys/dev/tty0/subsystem --> ../../class/tty
                /sys/dev/tty1/bus
                /sys/dev/tty1/subsystem --> ../../class/tty
                /sys/dev/tty2/bus
                /sys/dev/tty2/subsystem --> ../../class/tty

       The command fileutil::find currently has no way to escape this. When having to handle such
       a pathological hierarchy It is recommended to switch to package fileutil::traverse and the
       same-named  command  it  provides,  and  then  use  the  -prefilter  option to prevent the
       traverser from following symbolic links, like so:

                  package require fileutil::traverse

                  proc NoLinks {fileName} {
                      if {[string equal [file type $fileName] link]} {
                          return 0
                      }
                      return 1
                  }

                  fileutil::traverse T /sys/devices -prefilter NoLinks
                  T foreach p {
                      puts $p
                  }
                  T destroy

BUGS, IDEAS, FEEDBACK

       This document, and the package it describes,  will  undoubtedly  contain  bugs  and  other
       problems.    Please   report  such  in  the  category  fileutil  of  the  Tcllib  Trackers
       [http://core.tcl.tk/tcllib/reportlist].  Please also report any ideas for enhancements you
       may have for either package and/or documentation.

       When proposing code changes, please provide unified diffs, i.e the output of diff -u.

       Note further that attachments are strongly preferred over inlined patches. Attachments can
       be made by going to the Edit form of the ticket immediately after its creation,  and  then
       using the left-most button in the secondary navigation bar.

KEYWORDS

       cat, file utilities, grep, temp file, test, touch, type

NAME

SYNOPSIS

DESCRIPTION

WARNINGS AND INCOMPATIBILITIES

BUGS, IDEAS, FEEDBACK

KEYWORDS

CATEGORY