Hey, hrishy!

Itsn't that difficult write one on your own. All you need to do is:
Set up oracle_home and oracle_sid in shell script and call the sql script as follows.

Unix script
<font face=courier>
setenv ORAENV_ASK NO
setenv ORACLE_SID xyz
source /usr/bin/coraenv
sqlplus -s abc/**** @coal_tbs.sql
</font>
SQL script(coal_tbs.sql)
<font face=courier>
set echo off
set feedback off
set heading off
spool coaltbs.sql

select 'alter tablespace '||tablespace_name||' coalesce ;' from dba_tablespaces;

spool off
set feedback on
set echo on
</font>