Class: File
- Inherits:
-
Object
- Object
- File
- Defined in:
- lib/ptools.rb
Constant Summary collapse
- PTOOLS_VERSION =
'1.1.6'
- IS_WINDOWS =
false
- IMAGE_EXT =
%w/.bmp .gif .jpg .jpeg .png/
Class Method Summary collapse
-
.binary?(file) ⇒ Boolean
Returns whether or not
file
is a binary file. -
.head(filename, num_lines = 10) ⇒ Object
In block form, yields the first
num_lines
fromfilename
. -
.image?(file) ⇒ Boolean
Returns whether or not the file is an image.
-
.middle(filename, from = 10, to = 20) ⇒ Object
In block form, yields line
from
up to lineto
. -
.nl_convert(filename, newfilename = filename, platform = "dos") ⇒ Object
Converts a text file from one OS platform format to another, ala ‘dos2unix’.
-
.null ⇒ Object
Returns the null device (aka bitbucket) on your platform.
-
.tail(filename, num_lines = 10) ⇒ Object
In block form, yields the last
num_lines
of filefilename
. -
.touch(filename) ⇒ Object
Changes the access and modification time if present, or creates a 0 byte file
filename
if it doesn’t already exist. -
.wc(filename, option = 'all') ⇒ Object
With no arguments, returns a four element array consisting of the number of bytes, characters, words and lines in filename, respectively.
-
.whereis(program, path = ENV['PATH']) ⇒ Object
In block form, yields each
program
withinpath
. -
.which(program, path = ENV['PATH']) ⇒ Object
Looks for the first occurrence of
program
withinpath
.
Class Method Details
.binary?(file) ⇒ Boolean
Returns whether or not file
is a binary file. Note that this is not guaranteed to be 100% accurate. It performs a “best guess” based on a simple test of the first File.blksize
characters. – Based on code originally provided by Ryan Davis (which, in turn, is based on Perl’s -B switch).
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# File 'lib/ptools.rb', line 65 def self.binary?(file) s = (File.read(file, File.stat(file).blksize) || "").split(//) ((s.size - s.grep(" ".."~").size) / s.size.to_f) > 0.30 end |
.head(filename, num_lines = 10) ⇒ Object
In block form, yields the first num_lines
from filename
. In non-block form, returns an Array of num_lines
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# File 'lib/ptools.rb', line 149 def self.head(filename, num_lines=10) a = [] IO.foreach(filename){ |line| break if num_lines <= 0 num_lines -= 1 if block_given? yield line else a << line end } return a.empty? ? nil : a # Return nil in block form end |
.image?(file) ⇒ Boolean
Returns whether or not the file is an image. Only JPEG, PNG, BMP and GIF are checked against.
This method does some simple read and extension checks. For a version that is more robust, but which depends on a 3rd party C library (and is difficult to build on MS Windows), see the ‘filemagic’ library, available on the RAA. – Approach used here is based on information found at en.wikipedia.org/wiki/Magic_number_(programming)
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# File 'lib/ptools.rb', line 34 def self.image?(file) bool = IMAGE_EXT.include?(File.extname(file).downcase) # Match ext bool = bmp?(file) || jpg?(file) || png?(file) || gif?(file) # Check data bool end |
.middle(filename, from = 10, to = 20) ⇒ Object
In block form, yields line from
up to line to
. In non-block form returns an Array of lines from from
to to
.
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# File 'lib/ptools.rb', line 166 def self.middle(filename, from=10, to=20) if block_given? IO.readlines(filename)[from-1..to-1].each{ |line| yield line } else IO.readlines(filename)[from-1..to-1] end end |
.nl_convert(filename, newfilename = filename, platform = "dos") ⇒ Object
Converts a text file from one OS platform format to another, ala ‘dos2unix’. Valid values for ‘format’, which are case insensitve, include:
-
MS Windows -> dos, windows, win32, mswin
-
Unix/BSD -> unix, linux, bsd
-
Mac -> mac, macintosh, apple, osx
Note that this method is only valid for an ftype of “file”. Otherwise a TypeError will be raised. If an invalid format value is received, an ArgumentError is raised.
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# File 'lib/ptools.rb', line 203 def self.nl_convert(filename, newfilename=filename, platform="dos") unless File.ftype(filename) == "file" raise TypeError, "Only valid for plain text files" end if platform =~ /dos|windows|win32|mswin/i format = "\cM\cJ" elsif platform =~ /unix|linux|bsd/i format = "\cJ" elsif platform =~ /mac|apple|macintosh|osx/i format = "\cM" else raise ArgumentError, "Invalid platform string" end orig = $\ $\ = format if filename == newfilename require "ftools" require "tempfile" tf = Tempfile.new("temp") tf.open IO.foreach(filename){ |line| line.chomp! tf.print line } tf.close File.delete(filename) File.copy(tf.path,filename) else nf = File.new(newfilename,"w+") IO.foreach(filename){ |line| line.chomp! nf.print line } nf.close end $\ = orig self end |
.null ⇒ Object
Returns the null device (aka bitbucket) on your platform. On most Unix-like systems this is ‘/dev/null’, on Windows it’s ‘NUL’, etc. – Based on information from en.wikipedia.org/wiki//dev/null
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# File 'lib/ptools.rb', line 45 def self.null case RUBY_PLATFORM when /mswin/i 'NUL' when /amiga/i 'NIL:' when /openvms/i 'NL:' else '/dev/null' end end |
.tail(filename, num_lines = 10) ⇒ Object
In block form, yields the last num_lines
of file filename
. In non-block form, it returns the lines as an array.
Note that this method slurps the entire file, so I don’t recommend it for very large files. Also note that ‘tail -f’ functionality is not present.
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# File 'lib/ptools.rb', line 181 def self.tail(filename, num_lines=10) if block_given? IO.readlines(filename).reverse[0..num_lines-1].reverse.each{ |line| yield line } else IO.readlines(filename).reverse[0..num_lines-1].reverse end end |
.touch(filename) ⇒ Object
Changes the access and modification time if present, or creates a 0 byte file filename
if it doesn’t already exist.
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# File 'lib/ptools.rb', line 249 def self.touch(filename) if File.exists?(filename) time = Time.now File.utime(time, time, filename) else File.open(filename, 'w'){} end self end |
.wc(filename, option = 'all') ⇒ Object
With no arguments, returns a four element array consisting of the number of bytes, characters, words and lines in filename, respectively.
Valid options are ‘bytes’, ‘characters’ (or just ‘chars’), ‘words’ and ‘lines’.
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# File 'lib/ptools.rb', line 265 def self.wc(filename, option='all') option.downcase! valid = %w/all bytes characters chars lines words/ unless valid.include?(option) raise ArgumentError, "Invalid option: '#{option}'" end n = 0 if option == 'lines' IO.foreach(filename){ n += 1 } return n elsif option == 'bytes' File.open(filename){ |f| f.each_byte{ n += 1 } } return n elsif option == 'characters' || option == 'chars' File.open(filename){ |f| while f.getc n += 1 end } return n elsif option == 'words' IO.foreach(filename){ |line| n += line.split.length } return n else bytes,chars,lines,words = 0,0,0,0 IO.foreach(filename){ |line| lines += 1 words += line.split.length chars += line.split('').length } File.open(filename){ |f| while f.getc bytes += 1 end } return [bytes,chars,words,lines] end end |
.whereis(program, path = ENV['PATH']) ⇒ Object
In block form, yields each program
within path
. In non-block form, returns an array of each program
within path
.
On Windows, it looks for executables ending with the suffixes defined in your PATHEXT environment variable, or ‘.exe’, ‘.bat’ and ‘.com’ if that isn’t defined, which you may optionally include in program
.
Returns nil if not found.
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# File 'lib/ptools.rb', line 117 def self.whereis(program, path=ENV['PATH']) dirs = [] programs = program.to_a # If no file extension is provided on Windows, try the WIN32EXT's in turn if IS_WINDOWS && File.extname(program).empty? unless WIN32EXTS.include?(File.extname(program).downcase) WIN32EXTS.each{ |ext| programs.push(program + ext) } end end path.split(File::PATH_SEPARATOR).each{ |dir| programs.each{ |prog| file = File.join(dir,prog) file.tr!('/', File::ALT_SEPARATOR) if File::ALT_SEPARATOR if File.executable?(file) && !File.directory?(file) if block_given? yield file else dirs << file end end } } dirs.empty? ? nil : dirs.uniq end |
.which(program, path = ENV['PATH']) ⇒ Object
Looks for the first occurrence of program
within path
.
On Windows, it looks for executables ending with the suffixes defined in your PATHEXT environment variable, or ‘.exe’, ‘.bat’ and ‘.com’ if that isn’t defined, which you may optionally include in program
.
Returns nil if not found.
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# File 'lib/ptools.rb', line 78 def self.which(program, path=ENV['PATH']) programs = program.to_a # If no file extension is provided on Windows, try the WIN32EXT's in turn if IS_WINDOWS && File.extname(program).empty? unless WIN32EXTS.include?(File.extname(program).downcase) WIN32EXTS.each{ |ext| programs.push(program + ext) } end end # Catch the first path found, or nil location = catch(:done){ path.split(File::PATH_SEPARATOR).each{ |dir| programs.each{ |prog| f = File.join(dir, prog) if File.executable?(f) && !File.directory?(f) location = File.join(dir, prog) location.tr!('/', File::ALT_SEPARATOR) if File::ALT_SEPARATOR throw(:done, location) end } } nil # Evaluate to nil if not found } location end |