This is example of SHOW FILE for a user installed file (UIF).
SHOW FILE mapper;
Result:
*** Text of DDL statement returned.
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CALL SYSUIF.INSTALL_FILE('mapper','mapper.py','cz!mapper.py!/tmp/mapper.py')
*** Text of DDL statement returned.
----------------------------------------------------------------------------------
#!/usr/bin/python
import sys
# input comes from STDIN (standard input)
for line in sys.stdin:
# remove leading and trailing whitespace
line = line.strip()
# split the line into words
words = line.split()
# increase counters
for word in words:
# write the results to STDOUT (standard output);
# what we output here will be the input for the
# Reduce step, i.e. the input for reducer.py
#
# tab-delimited; the trivial word count is 1
print '%s\t%s' % (word, 1)