Clojure Execute Shell Command - dump postgres

Question

I am trying to execute this code:

(define dump-db []
 (. (Runtime/getRuntime) exec "pg_dump database-name | gzip -c > db-name.out.gz"))

But the db-name.out.gz file does not is created. Other commands like "ls" or "touch foo.txt" were successfully executed.

Any help?

What happens if you don't pipe to gzip? "pg_dump database-name > db-name.out" ? — S.L. Barth is on codidact.com, Jan 26 '15 at 14:15
Possible duplicate [(Java) File redirection (both ways) within Runtime.exec?](http://stackoverflow.com/questions/6795924/java-file-redirection-both-ways-within-runtime-exec). — juan.facorro, Jan 26 '15 at 14:18
@elf Please check the contents of the output stream from `Process.getOutputStream()` that `Runtime.exec()` returns. The result from the command should be there. AFAICT stdout and stdin redirection don't work when using `ProcessBuilder` or `Runtime.exec()`. — juan.facorro, Jan 26 '15 at 14:28
piping and redirecting are "shell features". if in doubt you can "always" use `sh -c 'mycommand | shellfeature > pipetofile'` — cfrick, Jan 27 '15 at 00:27

score 0 · Answer 1 · answered Jan 26 '15 at 15:09

I use this code for now:

(defn foo [line]
(with-open [wrtr (writer "/tmp/test.txt" :append true)]
  (.write wrtr (str line "\n"))))

(->> (.. Runtime getRuntime (exec "pg_dump db-name") getInputStream)
     java.io.InputStreamReader.
     java.io.BufferedReader.
     line-seq
     (map foo))

Clojure Execute Shell Command - dump postgres

1 Answers1