[HADOOP-13079] Add -q option to Ls to print ? instead of non-printable characters

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Assignee: John Zhuge
• Reporter: John Zhuge
• Created: 02/May/16 15:22
• Updated: 29/May/18 17:21
• Resolved: 13/Jun/16 18:46

Description

Add option -q to "hdfs dfs -ls" to print non-printable characters as "?". Non-printable characters are defined by isprint(3) 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.

Issue Links

• breaks: HADOOP-14199 TestFsShellList.testList fails on windows: illegal filenames
• breaks: HADOOP-13314 Remove 'package-info.java' from 'test\java\org\apache\hadoop\fs\shell\' to remove eclipse compile error
• is duplicated by: HDFS-4821 It's possible to create files with special characters in the filenames, but 'hadoop fs -ls' gives no indication
• is required by: HADOOP-13093 Discuss whether dfs -ls should escape control characters on terminal
• relates to: HDFS-240 Should HDFS restrict the names used for files?
• relates to: HADOOP-15496 TestFsShellList#testList fails on Windows