Two shell program questions, help to see

女狼一共舞

1.Write a shell script to display the odd lines of a given file.
2. Write a shell script using a directory as input, if the input is null, use current directory as input. The routine is used to find all files with suffix ".c" and ".cpp", and then compare each other to check out whether there exist two files having the same contents: if exist, print out the corresponding names of these files.

godxuli

#!/bin/sh
#for odd line
FLAG=1
for loop in `cat $1`
do
if [$FLAG -eq "1" ]; then
echo $loop
FLAG=0
else
FLAG=1
fi
done

hunter410

1:
sed -n'p;n' file

phoinix

1:
sed -n '1,${p;n}' file