unix - head AND tail of file

Question

Say you have a txt file, what is the command to view the top 10 lines and bottom 10 lines of file simultaneously?

i.e. if the file is 200 lines long, then view lines

Answer 1

To handle pipes (streams) as well as files, add this to your .bashrc or .profile file:

headtail() { awk -v offset="$1" '{ if (NR <= offset) print; else { a[NR] = $0; delete a[NR-offset] } } END { for (i=NR-offset+1; i<=NR; i++) print a[i] }' ; }

Then you can not only

headtail 10 < file.txt

but also

a.out | headtail 10

(This still appends spurious blank lines when 10 exceeds the input's length, unlike plain old a.out | (head; tail). Thank you, previous answerers.)

Note: headtail 10, not headtail -10.