Rio - Ruby I/O Facilitator

Rio is a facade for most of the standard ruby classes that deal with I/O; providing a simple, intuitive, succinct interface to the functionality provided by IO, File, Dir, Pathname, FileUtils, Tempfile, StringIO, OpenURI and others. Rio also provides an application level interface which allows many common I/O idioms to be expressed succinctly.

HOWTO…

Read a single file

ario = rio('afile')
string = ""
array = []

• Read a file into a string.

method 1

string = ario.contents

method 2

ario > string

• Append a file onto a string.

method 1

ario >> string

method 2

string += ario.contents

• Read lines of a file into an array

method 1

array = ario[]

method 2

ario > array

method 3

array = ario.to_a

method 4

array = ario.readlines

• Append lines of a file into an array

method 1

ario >> array

method 2

array += ario.lines[]

• Read the first 10 lines of a file into an array

method 1

array = ario[0...10]

method 2

array = ario.lines[0...10]

method 3

ario.lines(0...10) > array

• Read lines of a file into an array, with each line chomped

method 1

array = ario.chomp[]

method 2

array = ario.chomp.lines[]

method 3

ario.chomp > array

• Append the first 10 lines of a file into an array, with each line chomped

method 1

array += ario.chomp[0...10]

method 2

array += ario.chomp.lines[0...10]

method 3

ario.chomp.lines(0...10) >> array

• Read all lines starting with ‘require’ into an array, with each line chomped

method 1

array = ario.chomp[/^\s*require/]

method 2

array = ario.chomp.lines[/^\s*require/]

method 3

ario.chomp.lines(/^\s*require/) > array

• Read a gzipped file into a string

method 1

rio('afile.gz').gzip > string

method 2

string = rio('afile.gz').gzip.contents

• Append a gzipped file into a string

method 1

rio('afile.gz').gzip >> string

method 2

string += rio('afile.gz').gzip.contents

• Iterate through all the lines of a file

method 1

rio('afile').lines { |line| ... }

method 2

rio('afile').each { |line| ... }

method 3

rio('afile').each_line { |line| ... }

• Iterate through the lines of a gzipped file

rio('afile.gz').gzip { |line| ... }

• Iterate through all non-empty lines of a gzipped file, with each line chomped

rio('afile.gz').gzip.chomp.skiplines(:empty?) { |line| ... }

• Iterate through the first 100 lines of a file

method 1

rio('afile').lines(0...100) { |line| ... }

• Iterate through the first line and all ruby comment lines in a gzipped file

rio('afile.rb.gz').gzip.lines(0,/^\s*#/) { |line| ... }

• Iterate through the lines of a ruby file that are neither empty nor comments, with all lines chomped

rio('afile.rb').chomp.skiplines(/^\s*#/,:empty?) { |line| ... }

• Read all the comment lines from a ruby file into an array with all lines chomped

method 1

array = rio('afile.rb').chomp[/^\s*#/]

method 2

array = rio('afile.rb').chomp.lines[/^\s*#/]

method 3

rio('afile.rb').chomp.lines(/^\s*#/) > array

• Read lines of a file into an array, with each line chomped, skipping any lines longer than 1024 chars

method 1

array = ario.chomp[proc{ |line| line.length <= 1024}]

method 2

ario.chomp.lines(proc{ |line| line.length <= 1024}) > array

method 3

array = ario.chomp.skiplines[proc{ |line| line.length > 1024}]

method 4

array = ario.chomp.lines(proc{ |line| line.length <= 1024}).to_a

---

Write to a single file

ario = rio('afile')
string = "A String\n"
array = ["Line 0\n","Line 1\n"]

• Write a string to a file, leaving the Rio open

method 1

ario.puts(string)

method 2

ario.print(string)

method 3

ario.noautoclose < string

• Write a string to a file and close the file

method 1

rio('afile') < string

method 2

ario.print!(string)

method 3

ario.print(string).close

• Append a string to a file, leaving the Rio open

method 1

ario.a.puts(string)

method 2

ario.a.print(string)

method 3

ario.noautoclose << string

• Append a string to a file and close the file

method 1

rio('afile') << string

method 2

rio('afile').a.print!(string)

method 3

rio('afile').a.print(string).close

• Write an array to a file, leaving the Rio open

method 1

ario = rio('afile').nocloseoncopy
ario << array

method 2

ario.noautoclose < array

• Write an array to a file and close the file

method 1

rio('afile') < array

---

Select records

ario = rio('afile')
string = ""
array = []

• Put lines one thru ten and line 100 into an array

method 1

array = ario[0..9,99]

method 2

array = ario.lines[0..9,99]

method 3

ario.lines(0..9,99) > array

• Put lines one thru ten,line 100 and lines starting with ‘rio4ruby’ into an array

method 1

array = ario[0..9,99,/^rio4ruby/]

method 2

array = ario.lines[0..9,99,/^rio4ruby/]

method 3

ario.lines(0..9,99,/^rio4ruby/) > array

• Put lines that are longer than 128 bytes into an array

method 1

array = ario[proc{ |l| l.length > 128}]

method 2

array = ario.lines[proc{ |l| l.length > 128}]

method 3

array = ario.skiplines[proc{ |l| l.length <= 128}]

method 4

array = ario.skip.lines[proc{ |l| l.length <= 128}]

• Copy all lines that do not start with ‘rio4ruby’ into another file

method 1

ario.skiplines(/^rio4ruby/) > rio('another_file')

method 2

ario.lines.skiplines(/^rio4ruby/) > rio('another_file')

method 3

rio('another_file') < ario.skiplines(/^rio4ruby/)

• Copy the first 10 lines and lines starting with ‘rio4ruby’, but exclude any lines longer than 128 bytes

method 1

ario.lines(0...10,/^rio4ruby/).skiplines(proc{ |l| l.length > 128}] > rio('another_file')

method 2

rio('another_file') < ario.lines(0...10,/^rio4ruby/).skiplines(proc{ |l| l.length > 128})

---

Select directory entries

ario = rio('adir')
string = ""
array = []

• Put all entries with the extension ’.txt’ into an array

method 1

array = ario['*.txt']

method 2

array = ario[/\.txt$/]

method 3

array = ario.entries['*.txt']

• Put all files with the extension ’.txt’ into an array

method 1

array = ario.files['*.txt']

method 2

array = ario.files[/\.txt$/]

method 3

array = ario.files['*.txt']

• Put all entries with the extension ’.txt’ into an array, including those in subdirectories

method 1

array = ario.all['*.txt']

method 2

array = ario.all[/\.txt$/]

method 3

array = ario.all.entries['*.txt']

• Put all entries with the extension ’.txt’ into an array, including those in subdirectories, except those

in subdirectories name ’.svn’ method 1

array = ario.norecurse('.svn').all['*.txt']

method 2

array = ario.norecurse(/^\.svn$/).all[/\.txt$/]

method 3

array = ario.norecurse('.svn').entries['*.txt']

method 4

array = ario.entries('*.txt').norecurse('.svn').to_a

method 5

array = ario.norecurse('.svn')['*.txt']

• Put all directories (recursively) into an array

method 1

array = ario.dirs[]

method 2

array = ario.dirs.to_a

• Put all entries (recursively) into an array, but limit the depth of recursion to 2

method 1

array = ario.norecurse(3).to_a

• Iterate through ruby files in a directory and subdirectories skipping

those in the ’.svn’, and ‘pkg’ directories method 1

is_ruby_exe = proc{ |f| f.executable? and f[0][0] =~ /^#!.+ruby/ }
ario.norecurse('.svn','pkg').files('*.rb',is_ruby_exe) { |f| ... }

method 2

is_ruby_exe = proc{ |f| f.executable? and f.gets =~ /^#!.+ruby/ }
ario.norecurse('.svn','pkg').files('*.rb',is_ruby_exe) { |f| ... }

• Put all files excluding those that are symlinks to files in an array

method 1

array = ario.skipfiles[:symlink?]

method 2

array = ario.skipfiles(:symlink?).files[]

method 3

array = ario.skipfiles(:symlink?).to_a

method 4

array = ario.files.skipfiles[:symlink?]

• Put all entries that are not files (or symlinks to files) into an array

method 1

array = ario.skipfiles[]

method 2

array = ario.skipfiles.to_a

• Put all entries that are symlinks to files into an array

method 1

array = ario.files[proc{|f| f.file? and f.symlink?}]

method 2

array = ario.files(proc{|f| f.file? and f.symlink?}).to_a

• Put all directories except those named ’.svn’ into an array

method 1

array = ario.skipdirs['.svn']

method 2

array = ario.skipdirs[/^\.svn$/]

method 3

array = ario.skipdirs('.svn').to_a

method 4

array = ario.skipdirs('.svn').dirs[]

method 5

array = ario.skipdirs('.svn')[]

---

Read and writing files

ario = rio('afile')
string = ""
array = []

• Copy the contents of one file into another file

method 1

rio('srcfile') > rio('dstfile')

method 2

rio('dstfile') < rio('srcfile')

method 3

rip('dstfile').print!(rio('srcfile').contents)

• Append the contents of one file to another file

method 1

rio('srcfile') >> rio('dstfile')

method 2

rio('dstfile') << rio('srcfile')

method 3

rip('dstfile').a.print!(rio('srcfile').contents)

• Copy the first 10 lines of one file to another file

method 1

rio('srcfile').lines(0...10) > rio('dstfile')

method 2

rio('dstfile') < rio('srcfile').lines(0...10)

method 3

rio('dstfile') < rio('srcfile').lines[0...10]

• Concatenate several files into one

method 1

rio('dstfile') < [ rio('src1'), rio('src2'), rio('src3') ]

method 2

rio('dstfile') < rio('src1') << rio('src2') << rio('src3')

• Copy a web page into a file

method 1

rio('http://ruby-doc.org/') > rio('afile')

method 2

rio('afile') < rio('http://ruby-doc.org/')

method 3

rio('afile').print!(rio('http://ruby-doc.org/').contents)

• Append the output of the daytime server running on the localhost to a file

method 1

rio("tcp://localhost:daytime") >> rio('afile')

method 2

rio("tcp:",'localhost','daytime') >> rio('afile')

method 3

rio('afile') << rio("tcp://:daytime")

method 4

rio('afile') << rio("tcp://:13")

• Copy the first line and all lines containing ‘http:’ to a file

method 1

rio('srcfile').lines(0,/http:/) > rio('dstfile')

method 2

rio('dstfile') < rio('srcfile').lines(0,/http:/)

method 3

rio('dstfile') < rio('srcfile').lines[0,/http:/]

method 4

• Create a gzipped copy of a file

method 1

rio('afile') > rio('afile.gz').gzip

method 2

rio('afile.gz').gzip < rio('afile')

method 3

rio('afile.gz').gzip.print!( rio('afile').contents )

• Create an ungzipped copy of a gzipped file

method 1

rio('afile') < rio('afile.gz').gzip

method 2

rio('afile.gz').gzip > rio('afile')

method 3

rio('afile').print!( rio('afile.gz').gzip.contents )

• Copy the first 100 lines of gzipped file on a webserver into a local file

method 1

rio('http://aserver/afile.gz').gzip.lines(0...100) > rio('afile')

• Create a file composed of a header from another file, the output of the ‘ps’ command, some text and

its creation time pulled from the daytime server running on your localhost method 1

rio('out') < [ rio('header'), rio(?-,'ps'), "Created on ", rio('tcp://:daytime') ]

method 2

rio('out') < rio('header') << rio(?-,'ps') << "Created on: " << rio("tcp://:daytime")

---

Reading multiple files

ario = rio('adir')
string = ""
array = []

• Count the lines of code in a directory tree of ruby source files

method 1

cnt = ario.all.files('*.rb').skiplines[/^\s*#/,/^\s*$/].size

method 2

cnt = ario.all.files('*.rb').skiplines(/^\s*#/,/^\s*$/).inject(0) { |sum,l|  sum += 1 }

• Concatanate the contents of all .txt files in a directory into an array

method 1

array = ario.lines.files['*.txt']

method 2

array = ario.files('*.txt').lines[]

method 3

ario.files('*.txt').lines > array

• Concatanate the first line of all .txt files in a directory into an array

method 1

array = ario.lines(0).files['*.txt']

method 2

array = ario.files('*.txt').lines[0]

method 3

ario.files('*.txt').lines(0) > array

• Copy all .txt files (but only their first ten lines) in a directory into another directiory

method 1

ario.files('*.txt').lines(0...10) > rio('another_dir')

---

Read and write using Standard IO

string = ""
array = []

• Prompt for input and return what was typed

method 1

ans = rio(?-).chomp.print("Type Something: ").gets

method 2

stdio = rio(?-).chomp
ans = stdio.print("Type Something: ").gets

• Create a Rio tied to stdin or stdout, depending on how it is used

stdio = rio(?-)

• Create a Rio tied to stderr

stderr = rio(?=)

• Write a string to stdout

method 1

rio(?-).puts("Hello World")

method 2

rio(?-) << "Hello World\n"

method 3

rio(?-) < "Hello World\n"

• Read a string from stdin with the input chomped

method 1

ans = rio(?-).chomp.gets

method 2

stdio = rio(?-).chomp
ans = stdio.gets

• Read from stdin until end of file with the result going into a string

method 1

rio(?-) >> string

method 2

rio(?-) > string

• Read from stdin until end of file with the chomped lines going into an array

method 1

rio(?-).chomp >> array

method 2

rio(?-).chomp > array

• Read from stdin until end of file with the result going into a file

method 1

rio(?-) > rio('afile')

method 2

rio('afile') < rio(?-)

• Read from stdin until end of file with the result appended to a file

method 1

rio(?-) >> rio('afile')

method 2

rio('afile') << rio(?-)

• Write a message to stderr

method 1

rio(?=).puts("Hello Error")

method 2

rio(?=) << "Hello Error\n"

method 3

rio(?=) < "Hello Error\n"

• Dump a file to stdout

method 1

rio('afile') > ?-

method 2

rio('afile') > rio(?-)

method 3

rio(?-) << rio('afile')

method 4

rio('afile') >> ?-

method 5

rio(?-) < rio('afile')

method 6

rio(?-).print(rio('afile').contents)

• Emulate a simplified unix ‘head’ command which reads from stdin and writes the first 10 lines to stdout

method 1

rio(?-).lines(0..9) > ?-

---

Reading and writing from processes as one might do with popen

• Read the output of the ‘ps’ command into an array without the header line or the line representing

the ‘ps’ command itself

ps =  rio(?-,'ps -a').skiplines[0,/ps$/]

• Run an external program, copying its input from one location and its output to another,

and make it look very much like a shell command.

infile = rio(?","Hello Kitty\n")
outfile = rio('out.txt')

method 1

cat = rio(?-,'cat').w!
cat <infile>outfile

method 2

infile | 'cat' | outfile

---

Renaming and moving files

string = ""
array = []

• Rename the file ‘a’ to ‘b’

method 1

rio('a').rename('b')

method 2

rio('a').rename.filename = 'b'

• Rename a file and leave the Rio referencing the files old name

ario = rio('a')

method 1

ario.rename('b')

• Rename a file and change the Rio to reference the new file name

ario = rio('a')

method 1

ario.rename!('b')

• Rename the file ‘index.htm’ to ‘index.html’

method 1

rio('index.htm').rename('index.html')

method 2

rio('index.htm').rename.extname = '.html'

• Rename the file ‘index.html’ to ‘welcome.html’

method 1

rio('index.html').rename('welecome.html')

method 2

rio('index.htm').rename.basename = 'welcome'

• Move a file from directory ‘src’ to directory ‘dst’

method 1

rio('src/afile').rename('dst/afile')

method 2

rio('src/afile').rename.dirname = 'dst'

• Change a file to have the extension ’.html’ leaving the rest of it as is

method 1

ario.rename.extname = '.html'

• Change a files basename to ‘rio4ruby’ without changing its extension

method 1

ario.rename.basename = 'rio4ruby'

• Change a file ending with ’.tar.gz’ to end with ’.tgz’

method 1

ario.rename.ext('.tar.gz').extname = '.tgz'

• Change the extension of all files with the extension ’.htm’ in a directory to have the

extension ’.html’ method 1

rio('adir').rename.files('*.htm') do |htmfile|
  htmlfile.extname = '.html'
end

method 2

rio('adir').files('*.htm') do |htmfile|
  htmlfile.rename.extname = '.html'
end

• Change the extension of all files with the extension ’.htm’ in a directory and its

subdirectories to have the extension ’.html’ method 1

rio('adir').rename.all.files('*.htm') do |htmfile|
  htmfile.extname = '.html'
end

method 2

rio('adir').all.files('*.htm') do |htmfile|
  htmfile.rename.extname = '.html'
end

• Move a file in an arbitrary directory into the current working directory.

method 1

rio('arb/i/trary/di/rec/tory/afile').rename.dirname = '.'

---

Manipulate a Rio’s path

string = ""
array = []

• Create a Rio with an additional subdirectory appended

ap = rio('adir')

method 1

ap /= 'subdirectory'

method 2

ap = ap.join('subdirectory')

method 3

ap = rio(ap,'subdirectory')

• Create a Rio from an array of subdirectories

dirs = ['adir','subdir1','subdir2']

method 1

ario = rio(dirs)

• Create an array of subdirectories from a Rio

method 1

anarray = rio('adir/subdir1/subdir2').split

• Append a string to a path

method 1

ario = rio('apath') + astring

method 2

ario = rio('apath')
ario += astring

• create a directory ‘links’ with a symlink pointing to each .rb file in directory ‘lib’ (including subdirectories)

lib = rio('lib')
links = rio('links').delete!.mkdir
lib.all.files("*.rb") do |f|
  f.symlink( f.dirname.sub(/^#{lib}/,links).mkdir )
end

---

Suggested Reading

• RIO::Doc::SYNOPSIS
• RIO::Doc::INTRO
• RIO::Rio</infile>