[ http://issues.apache.org/jira/browse/HADOOP-477?page=comments#action_12431136 ] Owen O'Malley commented on HADOOP-477: --------------------------------------
I should mention that there is a "standard" trick for scripts where you can't assume that the tool is in the same location on all machines where the script will run. Namely, #!/usr/bin/env python <... python script ...> because the env command is always in /usr/bin and it will search the path for the command to run (in this case python). I just used python as an example, but this works for any scripting language. > Streaming should execute Unix commands and scripts in well known languages > without user specifying the path > ----------------------------------------------------------------------------------------------------------- > > Key: HADOOP-477 > URL: http://issues.apache.org/jira/browse/HADOOP-477 > Project: Hadoop > Issue Type: Bug > Components: contrib/streaming > Reporter: arkady borkovsky > > If the executables for -mapper or -reducer are well-known (grep, cat, awk), > Streaming should make sure that the executable is found. > If a script for -mapper or -reducer are in a well-known language (.pl, .py), > Streaming should execute it with the correct language processor. > Reason: > many jobs get started from machines with a different environment from that on > the cluster. > On another hand, different clusters may have different environments. > Also, a user may have no access to the cluster machines. > Because of this, a user may be unable to specify correct paths for standard > commands, and correct language processors for scripts. > Implementation: > Stream may tailr the commands by prepending the path, or the name of language > processor. > Another solution is to make sure that the commands are executed in a > "meaningful" environment (with good $PATH, and other variables Unix users are > accustomed to count upon). > Once again, Streaming is user facing tool -- it is not a library or a > hackable example that the users are to modify for their needs. So it should > work out of the box. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
