how can I combine these lines

Question

How can I combine these lines (NOTE: this is just an excerpt from a much larger file):

interface GigabitEthernet0/0
 no ip proxy-arp
interface GigabitEthernet0/0         


        

Answer 1

 awk '{printf "%s%s",$0,(NR%2?"|":"\n")}' file

Answer 2

while IFS= read line1 && IFS= read line2; do
    printf "%s | %s\n" "$line1" "$line2"
done < file.txt

Answer 3

Try this sed one-liner:

sed 'N;s/\n/ | /;s/\r//g' file.txt

Answer 4

paste can do it:

paste -d '|' - - < file