How to output all lines of a file without the last line?

Question

What is the best way to output all lines of a file without the last line, using command-line tools?

Example:

$ cat foo.txt
a b c
v w x y z
a sd dsgdfg 

$ some-cmd foo.txt
a b c
v w x y z

Answer 1

BASH, using head:

$ head --lines=-1 filename

Same for Mac:

expr "$a" : '\(.*\)
'

The newline is required!