How to redirect stderr and stdout to a file for Ruby script?

Question

How to redirect stderr and stdout to a file for Ruby script?

Answer 1

Inside the Ruby script, you can redirect stdout and stderr using the IO#reopen .

 # a.rb $stdout.reopen("out.txt", "w") $stderr.reopen("err.txt", "w") puts 'normal output' warn 'something to stderr' 

 $ ls
 a.rb
 $ ruby ​​a.rb
 $ ls
 a.rb err.txt out.txt
 $ cat err.txt 
 something to stderr
 $ cat out.txt 
 normal output

Answer 2

Note: reopening standard threads in / dev / null is a good old method to help a process become a daemon. For example:

 # daemon.rb $stdout.reopen("/dev/null", "w") $stderr.reopen("/dev/null", "w") 

Answer 3

 def silence_stdout $stdout = File.new( '/dev/null', 'w' ) yield ensure $stdout = STDOUT end 

Answer 4

 ./yourscript.rb 2>&1 > log.txt 

redirects stdout and stderr to the same file.