UNIX for Dummies Questions & Answers

cat file.txt | while read line
do
  echo $line | \
  awk '{print $1" "$2}' | \
  tr " " "\n" | \
  sort -d | \
  tr "\n" " "
  echo -ne "`echo $line | awk '{print $3}'`\n"
done

awk '{if($2 < $1) print $2,$1,$3;else print}' file
1ouy_0-13-35 1zz2_15-43 1.12619901947

#!/usr/bin/env python

""" 

Sort the first two space-separated fields alphanumerically.

"""



import sys
import os
import getopt

#Get input file (optional)
opts, args = getopt.getopt(sys.argv[1:], 'i:')

input_file = ""

for value in args:

    #input file
    if os.path.isfile(value):
        input_file =  value
        break

#did the user pass an input file?
if input_file == "":

    #if not, did the user pipe in a file?
    if sys.stdin.isatty():
        sys.stderr.write("An input file name is required, or a file must be piped in.\n")
        sys.stderr.write("Exiting program.\n")
        sys.exit(1)

    else: 
        #use piped file
        input = sys.stdin

else:
    #use file name passed by user
    input = open(input_file, 'r')




for line in input:

    #split fields into an array
    fields = line.split(' ');

    #reverse first two fields if not in alphabetical order
    if fields[1] < fields[0]:
        fields[1], fields[0] = fields[0], fields[1]

    output = " ".join(fields)
    print output,