HADOOP-13522. Add %A and %a formats for fs -stat command to print permissions. Contributed by Alex Garbarini.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/permission/FsPermission.java

@@ -183,6 +183,18 @@ public class FsPermission implements Writable {
     return toShort();
   }
 
+  /**
+   * Returns the FsPermission in an octal format.
+   *
+   * @return short Unlike {@link #toShort()} which provides a binary
+   * representation, this method returns the standard octal style permission.
+   */
+  public short toOctal() {
+    int n = this.toShort();
+    int octal = (n>>>9&1)*1000 + (n>>>6&7)*100 + (n>>>3&7)*10 + (n&7);
+    return (short)octal;
+  }
+
   @Override
   public boolean equals(Object obj) {
     if (obj instanceof FsPermission) {

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Stat.java

@@ -31,6 +31,8 @@ import org.apache.hadoop.fs.FileStatus;
 /**
  * Print statistics about path in specified format.
  * Format sequences:<br>
+ *   %a: Permissions in octal<br>
+ *   %A: Permissions in symbolic style<br>
  *   %b: Size of file in blocks<br>
  *   %F: Type<br>
  *   %g: Group name of owner<br>
@@ -56,7 +58,8 @@ class Stat extends FsCommand {
   public static final String USAGE = "[format] <path> ...";
   public static final String DESCRIPTION =
     "Print statistics about the file/directory at <path>" + NEWLINE +
-    "in the specified format. Format accepts filesize in" + NEWLINE +
+    "in the specified format. Format accepts permissions in" + NEWLINE +
+    "octal (%a) and symbolic (%A), filesize in" + NEWLINE +
     "blocks (%b), type (%F), group name of owner (%g)," + NEWLINE +
     "name (%n), block size (%o), replication (%r), user name" + NEWLINE +
     "of owner (%u), modification date (%y, %Y)." + NEWLINE +
@@ -95,6 +98,12 @@ class Stat extends FsCommand {
         // this silently drops a trailing %?
         if (i + 1 == fmt.length) break;
         switch (fmt[++i]) {
+          case 'a':
+            buf.append(stat.getPermission().toOctal());
+            break;
+          case 'A':
+            buf.append(stat.getPermission());
+            break;
           case 'b':
             buf.append(stat.getLen());
             break;

hadoop-common-project/hadoop-common/src/site/markdown/FileSystemShell.md

@@ -639,11 +639,11 @@ stat
 
 Usage: `hadoop fs -stat [format] <path> ...`
 
-Print statistics about the file/directory at \<path\> in the specified format. Format accepts filesize in blocks (%b), type (%F), group name of owner (%g), name (%n), block size (%o), replication (%r), user name of owner(%u), and modification date (%y, %Y). %y shows UTC date as "yyyy-MM-dd HH:mm:ss" and %Y shows milliseconds since January 1, 1970 UTC. If the format is not specified, %y is used by default.
+Print statistics about the file/directory at \<path\> in the specified format. Format accepts permissions in octal (%a) and symbolic (%A), filesize in blocks (%b), type (%F), group name of owner (%g), name (%n), block size (%o), replication (%r), user name of owner(%u), and modification date (%y, %Y). %y shows UTC date as "yyyy-MM-dd HH:mm:ss" and %Y shows milliseconds since January 1, 1970 UTC. If the format is not specified, %y is used by default.
 
 Example:
 
-* `hadoop fs -stat "%F %u:%g %b %y %n" /file`
+* `hadoop fs -stat "%F %a %u:%g %b %y %n" /file`
 
 Exit Code: Returns 0 on success and -1 on error.
 

hadoop-common-project/hadoop-common/src/test/resources/testConf.xml

@@ -859,7 +859,11 @@
         </comparator>
         <comparator>
           <type>RegexpComparator</type>
-          <expected-output>^( |\t)*in the specified format. Format accepts filesize in( )*</expected-output>
+          <expected-output>^( |\t)*in the specified format. Format accepts permissions in( )*</expected-output>
+        </comparator>
+        <comparator>
+          <type>RegexpComparator</type>
+          <expected-output>^( |\t)*octal \(%a\) and symbolic \(%A\), filesize in( )*</expected-output>
         </comparator>
         <comparator>
           <type>RegexpComparator</type>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java

@@ -2021,17 +2021,31 @@ public class TestDFSShell {
         out.toString(), String.format("%s%n%s%n", mtime1, mtime2));
 
     doFsStat(dfs.getConf(), "%F %u:%g %b %y %n");
-
     out.reset();
-    doFsStat(dfs.getConf(), "%F %u:%g %b %y %n", testDir1);
+
+    doFsStat(dfs.getConf(), "%F %a %A %u:%g %b %y %n", testDir1);
     assertTrue(out.toString(), out.toString().contains(mtime1));
     assertTrue(out.toString(), out.toString().contains("directory"));
     assertTrue(out.toString(), out.toString().contains(status1.getGroup()));
+    assertTrue(out.toString(),
+        out.toString().contains(status1.getPermission().toString()));
+
+    int n = status1.getPermission().toShort();
+    int octal = (n>>>9&1)*1000 + (n>>>6&7)*100 + (n>>>3&7)*10 + (n&7);
+    assertTrue(out.toString(),
+        out.toString().contains(String.valueOf(octal)));
 
     out.reset();
-    doFsStat(dfs.getConf(), "%F %u:%g %b %y %n", testDir1, testFile2);
+    doFsStat(dfs.getConf(), "%F %a %A %u:%g %b %y %n", testDir1, testFile2);
+
+    n = status2.getPermission().toShort();
+    octal = (n>>>9&1)*1000 + (n>>>6&7)*100 + (n>>>3&7)*10 + (n&7);
     assertTrue(out.toString(), out.toString().contains(mtime1));
     assertTrue(out.toString(), out.toString().contains("regular file"));
+    assertTrue(out.toString(),
+        out.toString().contains(status2.getPermission().toString()));
+    assertTrue(out.toString(),
+        out.toString().contains(String.valueOf(octal)));
     assertTrue(out.toString(), out.toString().contains(mtime2));
   }