Module: FileUtils

Methods

head
head
safe_ln
safe_ln
slice
slice
tail
tail
wc
wc
whereis
whereis
which
which

Constants

Win32Exts	=	%w{.exe .com .bat .cmd}
Win32Exts	=	%w{.exe .com .bat .cmd}
LINKING_SUPPORTED	=	[true]
Win32Exts	=	%w{.exe .com .bat .cmd}
Win32Exts	=	%w{.exe .com .bat .cmd}
LINKING_SUPPORTED	=	[true]

Public Instance methods

head(filename,lines=10) {|| ...}

In block form, yields the first number of ((lines)) of file ((filename)). In non-block form, it returns an array of the first number of ((lines)).

  # Returns first 10 lines of 'myfile'
  FileUtils.head("myfile")

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 11
  def head(filename,lines=10) #:yield:
    a = []
    IO.foreach(filename){|line|
        break if lines <= 0
        lines -= 1
        if block_given?
          yield line
        else
          a << line
        end
    }
    return a.empty? ? nil : a
  end

head(filename,lines=10) {|| ...}

In block form, yields the first number of ((lines)) of file ((filename)). In non-block form, it returns an array of the first number of ((lines)).

  # Returns first 10 lines of 'myfile'
  FileUtils.head("myfile")

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 11
  def head(filename,lines=10) #:yield:
    a = []
    IO.foreach(filename){|line|
        break if lines <= 0
        lines -= 1
        if block_given?
          yield line
        else
          a << line
        end
    }
    return a.empty? ? nil : a
  end

safe_ln(*args)

Attempt to do a normal file link, but fall back to a copy if the link fails.

CREDIT Jim Weirich

[ show source ]

# File lib/lore/facets/fileutils/safe_ln.rb, line 14
  def safe_ln(*args)
    unless LINKING_SUPPORTED[0]
      cp(*args)
    else
      begin
        ln(*args)
      rescue Errno::EOPNOTSUPP
        LINKING_SUPPORTED[0] = false
        cp(*args)
      end
    end
  end

safe_ln(*args)

Attempt to do a normal file link, but fall back to a copy if the link fails.

CREDIT Jim Weirich

[ show source ]

# File lib/lore/facets/fileutils/safe_ln.rb, line 14
  def safe_ln(*args)
    unless LINKING_SUPPORTED[0]
      cp(*args)
    else
      begin
        ln(*args)
      rescue Errno::EOPNOTSUPP
        LINKING_SUPPORTED[0] = false
        cp(*args)
      end
    end
  end

slice(filename,from,to) {|| ...}

In block form, yields lines ((from))-((to)). In non-block form, returns an array of lines ((from))-((to)).

  # Returns lines 8-12 of 'myfile'
  FileUtils.body("myfile",8,12)

CREDIT Shashank Date, via Daniel Berger.

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 48
  def slice(filename,from,to) #:yield:
    IO.readlines(filename)[from-1..to-1]
  end

slice(filename,from,to) {|| ...}

In block form, yields lines ((from))-((to)). In non-block form, returns an array of lines ((from))-((to)).

  # Returns lines 8-12 of 'myfile'
  FileUtils.body("myfile",8,12)

CREDIT Shashank Date, via Daniel Berger.

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 48
  def slice(filename,from,to) #:yield:
    IO.readlines(filename)[from-1..to-1]
  end

tail(filename,lines=10)

In block form, yields the last number of ((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. If you want an advanced form of ((tail)), I suggest using file-tail, by Florian Frank (available on the RAA). And no tail -f.

  # Returns last 3 lines of 'myfile'
  FileUtils.tail("myfile",3)

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 36
  def tail(filename,lines=10) #:yield
    IO.readlines(filename).reverse[0..lines-1].reverse
  end

tail(filename,lines=10)

In block form, yields the last number of ((lines)) of file ((filename)). In non-block form, it returns the lines as an array.

  # Returns last 3 lines of 'myfile'
  FileUtils.tail("myfile",3)

[ show source ]

# File lib/lore/facets/fileutils/slice.rb, line 36
  def tail(filename,lines=10) #:yield
    IO.readlines(filename).reverse[0..lines-1].reverse
  end

wc(filename,option='all')

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.

  # Return the number of words in 'myfile'
  FileUtils.wc("myfile",'words')

CREDIT Daniel J. Berger

[ show source ]

# File lib/lore/facets/fileutils/wc.rb, line 16
  def wc(filename,option='all')
    option.downcase!
    valid = %w/all bytes characters chars lines words/

    unless valid.include?(option)
        raise "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

wc(filename,option='all')

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.

  # Return the number of words in 'myfile'
  FileUtils.wc("myfile",'words')

CREDIT Daniel J. Berger

[ show source ]

# File lib/lore/facets/fileutils/wc.rb, line 16
  def wc(filename,option='all')
    option.downcase!
    valid = %w/all bytes characters chars lines words/

    unless valid.include?(option)
        raise "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(prog, path=ENV['PATH']) {|| ...}

[ show source ]

# File lib/lore/facets/fileutils/whereis.rb, line 23
  def whereis(prog, path=ENV['PATH']) #:yield:
    dirs = []
    path.split(File::PATH_SEPARATOR).each{|dir|
        # Windows checks against specific extensions
        if File::ALT_SEPARATOR
          if prog.include?('.')
              f = File.join(dir,prog)
              if File.executable?(f) && !File.directory?(f)
                if block_given?
                    yield f.gsub(/\//,'\\')
                else
                    dirs << f.gsub(/\//,'\\')
                end
              end
          else
              Win32Exts.find_all{|ext|
                f = File.join(dir,prog+ext)
                if File.executable?(f) && !File.directory?(f)
                    if block_given?
                      yield f.gsub(/\//,'\\')
                    else
                      dirs << f.gsub(/\//,'\\')
                    end
                end
              }
          end
        else
          f = File.join(dir,prog)
          # Avoid /usr/lib/ruby, for example
          if File.executable?(f) && !File.directory?(f)
              if block_given?
                yield f
              else
                dirs << f
              end
          end
        end
    }
    dirs.empty? ? nil : dirs
  end

whereis(prog, path=ENV['PATH']) {|| ...}

[ show source ]

# File lib/lore/facets/fileutils/whereis.rb, line 23
  def whereis(prog, path=ENV['PATH']) #:yield:
    dirs = []
    path.split(File::PATH_SEPARATOR).each{|dir|
        # Windows checks against specific extensions
        if File::ALT_SEPARATOR
          if prog.include?('.')
              f = File.join(dir,prog)
              if File.executable?(f) && !File.directory?(f)
                if block_given?
                    yield f.gsub(/\//,'\\')
                else
                    dirs << f.gsub(/\//,'\\')
                end
              end
          else
              Win32Exts.find_all{|ext|
                f = File.join(dir,prog+ext)
                if File.executable?(f) && !File.directory?(f)
                    if block_given?
                      yield f.gsub(/\//,'\\')
                    else
                      dirs << f.gsub(/\//,'\\')
                    end
                end
              }
          end
        else
          f = File.join(dir,prog)
          # Avoid /usr/lib/ruby, for example
          if File.executable?(f) && !File.directory?(f)
              if block_given?
                yield f
              else
                dirs << f
              end
          end
        end
    }
    dirs.empty? ? nil : dirs
  end

which(prog, path=ENV['PATH'])

Looks for the first occurrence of program within path.

On the MS Windows platform, it looks for executables ending with .exe, .bat and .com, which you may optionally include in the program name. Returns nil if not found.

CREDIT Daniel J. Berger & Michael Granger

[ show source ]

# File lib/lore/facets/fileutils/which.rb, line 24
  def which(prog, path=ENV['PATH'])
    path.split(File::PATH_SEPARATOR).each {|dir|
      # Windows checks against specific extensions
      if File::ALT_SEPARATOR
        ext = Win32Exts.find{|ext|
          if prog.include?('.') # Assume extension already included
            f = File.join(dir,prog)
          else
            f = File.join(dir,prog+ext)
          end
          File.executable?(f) && !File.directory?(f)
        }
        if ext
          # Use backslashes, not forward slashes
          if prog.include?('.') # Assume extension already included
            f = File.join( dir, prog ).gsub(/\//,'\\')
          else
            f = File.join( dir, prog + ext ).gsub(/\//,'\\')
          end
          return f
        end
      else
        f = File.join(dir,prog)
        # Avoid /usr/lib/ruby, for example
        if File.executable?(f) && !File.directory?(f)
          return File::join( dir, prog )
        end
      end
    }
    nil
  end

which(prog, path=ENV['PATH'])

Looks for the first occurrence of program within path.

On the MS Windows platform, it looks for executables ending with .exe, .bat and .com, which you may optionally include in the program name. Returns nil if not found.

CREDIT Daniel J. Berger & Michael Granger

[ show source ]

# File lib/lore/facets/fileutils/which.rb, line 24
  def which(prog, path=ENV['PATH'])
    path.split(File::PATH_SEPARATOR).each {|dir|
      # Windows checks against specific extensions
      if File::ALT_SEPARATOR
        ext = Win32Exts.find{|ext|
          if prog.include?('.') # Assume extension already included
            f = File.join(dir,prog)
          else
            f = File.join(dir,prog+ext)
          end
          File.executable?(f) && !File.directory?(f)
        }
        if ext
          # Use backslashes, not forward slashes
          if prog.include?('.') # Assume extension already included
            f = File.join( dir, prog ).gsub(/\//,'\\')
          else
            f = File.join( dir, prog + ext ).gsub(/\//,'\\')
          end
          return f
        end
      else
        f = File.join(dir,prog)
        # Avoid /usr/lib/ruby, for example
        if File.executable?(f) && !File.directory?(f)
          return File::join( dir, prog )
        end
      end
    }
    nil
  end