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https://issues.apache.org/jira/browse/HADOOP-12830?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15158879#comment-15158879
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Kazuho Fujii commented on HADOOP-12830:
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[~aw],
bq. Not necessarily. If Kerberos is enabled, keys are being stored locked in
memory, etc, then su isn't guaranteed to work.
Thanks for teaching. If so, the security is a critical issue. I do not want to
downgrade the security level with this feature. I try to search a solution.
I will rewrite the patch following your advice. Thanks a lot.
> Bash environment for quick command operations
> ---------------------------------------------
>
> Key: HADOOP-12830
> URL: https://issues.apache.org/jira/browse/HADOOP-12830
> Project: Hadoop Common
> Issue Type: New Feature
> Components: bin
> Reporter: Kazuho Fujii
> Assignee: Kazuho Fujii
> Attachments: HADOOP-12830.001.patch
>
>
> Hadoop file system shell commands are slow. This issue is about building a
> shell environment for quick command operations.
> Previously an interactive shell is tried to build in HADOOP-6541. But, it
> seems to be poor because users are used to powerful shells like bash. This
> issue is not about creating a new shell, but just opening a new bash process.
> Therefore, user can operate commands as before.
> {code}
> fjk@x240:~/hadoop-2.7.2$ ./bin/hadoop shell
> fjk@x240 hadoop> hadoop fs -ls /
> Found 2 items
> -rw-r--r-- 3 fjk supergroup 0 2016-02-21 00:26 /file1
> -rw-r--r-- 3 fjk supergroup 0 2016-02-21 00:26 /file2
> {code}
> The shell has a mini daemon process that is living until the shell is closed.
> The hadoop fs command delegates the operation to the daemon. They communicate
> with named pipes. The daemon conducts the operation and returns the result to
> the command.
> In this shell the hadoop fs commands operation becomes quick. In a local
> environment, "hadoop fs -ls" command is about 100 times faster than the
> normal command.
> {code}
> fjk@x240 hadoop> time hadoop fs -ls hdfs://localhost:8020/ > /dev/null
> real 0m0.021s
> user 0m0.003s
> sys 0m0.011s
> {code}
> Using bash's function, commands and file names are automatically completed.
> {code}
> fjk@x240 hadoop> hadoop fs -ch<TAB><TAB>
> -checksum -chgrp -chmod -chown
> fjk@x240 hadoop> hadoop fs -ls /file<TAB><TAB>
> /file1 /file2 /file3
> {code}
> Additionally, we can make equivalents with bash build-in commands, e.g., cd,
> umask. In this shell, they can work because the daemon remembers the state.
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