Sometimes, I need to rename many files in a systematic way (either strip off some part of the filename or replace it with another string).
Although you can solve that problem using a shell scripting language and sed there is a lot of potential to mistype the sed command
resulting in data loss.
An obvious choice would have been to use perl, but I decided to give it a try with ruby.
Here is the result, may this can serve as a simple example (and hopefully not a good example of a bad example :) )
#!/usr/bin/ruby
# Project: rename files
# Date: Thu Sep 21 13:02:57 CEST 2006
# Author: Nicholas Stallard
# Description: change parts of a filename to something else
# get the command line parameters
require 'getoptlong'
# this is for the cvs
cvsversion = "$Revision: 1.9 $"
version = cvsversion.split.slice(1)
# program information
progname = File.basename($0,".rb")
proginfo = progname+" "+version
# parameter defaults
dofiles = FALSE
from = ""
to = ""
# get the options
opts = GetoptLong.new(
[ "--help", "-h", GetoptLong::NO_ARGUMENT ],
[ "--onlyfiles", "-o", GetoptLong::NO_ARGUMENT ],
[ "--from", "-f", GetoptLong::REQUIRED_ARGUMENT ],
[ "--to", "-t", GetoptLong::REQUIRED_ARGUMENT ],
[ "--uppercase", "-u", GetoptLong::REQUIRED_ARGUMENT ],
[ "--lowercase", "-l", GetoptLong::REQUIRED_ARGUMENT ],
[ "--capitalize", "-c", GetoptLong::REQUIRED_ARGUMENT ],
[ "--remove", "-r", GetoptLong::REQUIRED_ARGUMENT ]
)
# clean exit upon control-c
trap("INT") { exit 1 }
# show some help
def printusage (info, name)
puts info
puts
puts "Usage:"
puts
puts name+" [--onlyfiles] --from=<string> --to=<replacement string>"
puts
puts "Shortcuts:"
puts " --uppercase=<string>"
puts " --lowercase=<string>"
puts " --captialize=<string>"
puts " --remove=<string>"
puts
puts "The string transformation is applied to all items in the current directory"
puts "unless the option --onlyfiles is supplied, where only file names are manipulated"
puts
end
# if no argument was supplied, also display help :-)
if (ARGV.empty?)
printusage(proginfo, progname)
exit
end
# get the arguments
opts.each do |opt, arg|
case opt
when '--help'
printusage(proginfo, progname)
exit
when '--from'
from = arg
when '--to'
to = arg
when '--uppercase'
from = arg
to = from.upcase
when '--lowercase'
from = arg
to = from.downcase
when '--remove'
from = arg
to = ""
when '--capitalize'
from = arg
to = from.capitalize
when '--onlyfiles'
dofiles = TRUE
end
end
# there is a bug, some say it may be a feature :-)
# supplying --from without --to works like --remove
# set up an array containing all the items in the current directory
# matching the regular expression
filelist = Dir.glob("*")
# only rename files, omit directories
if dofiles
newfiles = Array.new
filelist.each do |d|
if File.file?(d)
newfiles.push(d)
end
end
filelist = newfiles
end
# And process each element within the array
filelist.each do |d|
# replace one string with another
nfn = d.gsub(/#{from}/, "#{to}")
# this will empty a string if it is full of whitespaces
nfn.strip!
# avoid mayhem and disallow empty names
if (nfn.empty?)
puts "Error: Resulting name would be empty!"
exit 1
end
# No need to rename if old and new name are identical
if ( d == nfn )
puts "Warning: Not renaming "+d+" (New name is identical to old one)"
next
end
# do not overwrite existing items
if ( File.file?(nfn) )
puts "Error: Cowardly refusing to rename "+d+" ("+nfn+" exists!)"
next
end
# and proceed with the rename operation
File.rename(d, nfn)
puts "Renamed "+d+" to "+nfn
end
exit 0
Simple Things 