LFE Friday - erl_tar:table/1

This week's LFE Friday was translated with permission from the Erlang Thursday series by Steven Proctor. This week's translator: Robert Virding.

Today's LFE Friday is on erl_tar:table/1.

erl_tar:table/1 returns a list of filenames included in the tar file.

> (erl_tar:table "animal_sounds.tar")  
#(ok ("dog.txt" "cat.txt" "pony.txt" "bear.txt"))

There is also a version erl_tar:table/2 that takes a options list as well.

> (erl_tar:table "animal_sounds.tar.gz" '(compressed)) 
#(ok ("dog.txt" "cat.txt" "pony.txt" "bear.txt"))
> (erl_tar:table "animal_sounds.tar.gz" '(compressed verbose))
#(ok
  (#("dog.txt" regular 5 #(#(2015 10 18) #(16 47 9)) 420 503 20)
   #("cat.txt" regular 5 #(#(2015 10 18) #(16 47 18)) 420 503 20)
   #("pony.txt" regular 8 #(#(2015 10 18) #(16 47 28)) 420 503 20)
   #("bear.txt" regular 19 #(#(2015 10 18) #(16 47 46)) 420 503 20)))

With the verbose option, instead of just getting a list of filenames, we get a list of tuples when we pass verbose.

The tuple is: file-name, file-type (regular file/directory or a symbolic link), bytes of the file, timestamp tuple, permissions (expressed in decimal instead of octal so 420 is #o644), user-id, and group-id.

The documentation does not specify any of the information about the return type, and the credit for clarification of what the 420 501 20 items represent is all from Robert Virding, from emailing him this post to be translated as part of LFE Fridays.

-Proctor, Robert