If Judge of Ruby

The basic format of the If judgment is as follows:

If condition then #then可省略 processing end

1. Determine if the file exists

#!/usr/bin/env rubyif file.exist? ("/etc/hosts") print "OK" end

Plus Else

#!/usr/bin/env rubyif file.exist? ("/etc/hosts") print "OK" else print "error,file not exist" end

If the program is running in the background, you will need to change the print to write log

#!/usr/bin/env rubyrequire ' logger ' logger = logger.new ('/tmp/test.log ', ' daily ') Logger.sev_threshold = logger::D Ebugif file.exist? ("/etc/hosts") logger.debug "OK" logger.closeelse logger.debug "error,file not Exist" Logger.closeend

2, judge whether the document can be written

If file.writable? ("/etc/hosts") {print "OK"}

3, judge whether the document is readable

If file.readable? ("/etc/hosts")

4. Determine if the file is executable

If file.executable? ("/etc/hosts")

5. Determine file size

If File.size? ("/etc/hosts") #文件大小非零为true

If File.zero? ("/etc/hosts") #文件大小为零位true

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If Judge of Ruby