head

Operator

  head — copy leading values of input sequence

Synopsis

head [ <const-expr> ]

Description

The head operator copies the first N values from its input to its output and ends the sequence thereafter. N is given by <const-expr>, a compile-time constant expression that evaluates to a positive integer. If <const-expr> is not provided, the value of N defaults to 1.

Examples

Grab first two values of arbitrary sequence

echo '1 "foo" [1,2,3]' | super -z -c 'head 2' -

=>

1
"foo"

Grab first two values of arbitrary sequence, using a different representation of two

echo '1 "foo" [1,2,3]' | super -z -c 'head 1+1' -

=>

1
"foo"

Grab the first record of a record sequence

echo '{a:"hello"}{b:"world"}' | super -z -c head -

=>

{a:"hello"}