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https://issues.apache.org/jira/browse/HADOOP-13079?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15268981#comment-15268981
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Colin Patrick McCabe commented on HADOOP-13079:
-----------------------------------------------
Thank you for the background information. I wasn't aware that the default of
suppressing non-printing characters was "optional" according to POSIX.
I think the important thing is that we've established that:
* Suppressing non-printing characters by default fixes several serious security
vulnerabilties, including some that have CVEs,
* This suppression behavior is explicitly allowed by POSIX,
* The most popular UNIX system on Earth, Linux, implements this behavior, so
nobody will be surprised by it.
bq. Essentially interactive sessions with stdin redirected \[falsely show up as
non-interactive from Java\]
I guess my concern about adding a JNI dependency here is that it will make
things too nondeterministic. I've seen too many clusters where JNI was
improperly configured.
> Add -q to fs -ls to print non-printable characters
> --------------------------------------------------
>
> Key: HADOOP-13079
> URL: https://issues.apache.org/jira/browse/HADOOP-13079
> Project: Hadoop Common
> Issue Type: Bug
> Reporter: John Zhuge
> Assignee: John Zhuge
> Labels: supportability
>
> Add option {{-q}} to "hdfs dfs -ls" to print non-printable characters as "?".
> Non-printable characters are defined by
> [isprint(3)|http://linux.die.net/man/3/isprint] according to the current
> locale.
> Default to {{-q}} behavior on terminal; otherwise, print raw characters. See
> the difference in these 2 command lines:
> * {{hadoop fs -ls /dir}}
> * {{hadoop fs -ls /dir | od -c}}
> In C, {{isatty(STDOUT_FILENO)}} is used to find out whether the output is a
> terminal. Since Java doesn't have {{isatty}}, I will use JNI to call C
> {{isatty()}} because the closest test {{System.console() == null}} does not
> work in some cases.
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