Shell Programming and Scripting

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#!/bin/sh

input_file="jiji.txt"

cut -d' ' -f1 $input_file | uniq |\
  while read val; do
  values=`sed -n "/^${val} / p" $input_file`
  if [ `echo "$values" | wc -l` -eq 1 ]; then
     echo "$values"
  else
     first=`echo "$values" | sed -n '1 p'`
     last=`echo "$values" | sed -n '$ p'`
     echo "$first"
     echo "$last"
  fi
done

exit 0

1 234
1 348
3 123
3 125
5 483
7 132
7 244
9 123
10 123
10 194