Remove the Junk charcters from hive tables or from unix - sql

Question

We have the tables in hive like below and we are generating the flat files from hive data while we are generating we found that there was junk characteres with in the data like below we have many characters in many columns can any one help us to remove those junk characters from hive table or from unix file ?
ÿ,ä,í,ã
Here problem the same data need to send the downstream when they are loading in to there DB it shows as double dollar but we design code double dollar as column delimiter.

Answer 1

Basic concept
hive> select regexp_replace('Hÿelloä íworlãd','[^a-zA-Z ]','');
OK
Hello world
Demo
Removing undesired character from the whole table and exporting it to a file.
create table t (i int,s1 string,s2 string);
insert into t values (1,'Hÿelloä','íworlãd'),(2,'ãGããood','Byÿe');
select * from t;
+---+---------+---------+
| i | s1 | s2 |
+---+---------+---------+
| 1 | Hÿelloä | íworlãd |
| 2 | ãGããood | Byÿe |
+---+---------+---------+
create external table t_ext (rec string)
row format delimited
fields terminated by '0'
location '/user/hive/warehouse/t'
;
insert overwrite local directory '/tmp/t_ext'
select regexp_replace(regexp_replace(rec,'[^a-zA-Z0-9 \\01]',''),'\\x01','<--->')
from t_ext
;
! ls /tmp/t_ext
;
000000_0
! cat /tmp/t_ext/000000_0
;
1<--->Hello<--->world
2<--->Good<--->Bye

Answer 2

This works as long as your tables contain only "primitive" types (no structs, arrays, maps etc.).
I really pushed the envelope here.
Demo
create table t (i int, dt date, str string, ts timestamp, bl boolean);
insert into t select 1,current_date,'Hello world',current_timestamp,true;
select * from t;
+-----+------------+-------------+-------------------------+------+
| t.i | t.dt | t.str | t.ts | t.bl |
+-----+------------+-------------+-------------------------+------+
| 1 | 2017-03-14 | Hello world | 2017-03-14 14:37:28.889 | true |
+-----+------------+-------------+-------------------------+------+
select regexp_replace
(
printf(concat('%s',repeat('$$%s',field(unhex(1),*,unhex(1))-2)),*)
,'(\\$\\$)|[^a-zA-Z0-9 -]'
,'$1'
)
from t
;
1$$2017-03-14$$Hello world$$2017-03-14 143728.889$$true