HADOOP-16167. Fixed Hadoop shell script for Ubuntu 18. (#44)

Contributed by Daniel Templeton

(cherry picked from commit 5446e3c)
(cherry picked from commit 11d6c4e)

Co-authored-by: Eric Yang <[email protected]>

Author: prabhjyotsingh

hadoop-common-project/hadoop-common/src/main/bin/hadoop-functions.sh

@@ -2361,6 +2361,10 @@ function hadoop_verify_user_perm
   declare command=$2
   declare uvar
 
+  if [[ ${command} =~ \. ]]; then
+    return 1
+  fi
+
   uvar=$(hadoop_build_custom_subcmd_var "${program}" "${command}" USER)
 
   if [[ -n ${!uvar} ]]; then
@@ -2392,6 +2396,10 @@ function hadoop_need_reexec
     return 1
   fi
 
+  if [[ ${command} =~ \. ]]; then
+    return 1
+  fi
+
   # if we have privilege, and the _USER is defined, and _USER is
   # set to someone who isn't us, then yes, we should re-exec.
   # otherwise no, don't re-exec and let the system deal with it.
@@ -2428,6 +2436,10 @@ function hadoop_subcommand_opts
     return 1
   fi
 
+  if [[ ${command} =~ \. ]]; then
+    return 1
+  fi
+
   # bash 4 and up have built-in ways to upper and lower
   # case the contents of vars.  This is faster than
   # calling tr.