Usage:

head file ...

Print the first 10 lines of each file to standard output.
With more than one file, precede each with a header giving the file name.
With no file, or when file is -, read standard input.

• $ head -f file1

  
  

  $ head -n 50 file1

The following options can be used:

-c, --bytes=[-]NUM       print the first NUM bytes of each file; with the leading '-', print all but the last NUM bytes of each file
-n, --lines=[-]NUM       print the first NUM lines instead of the first 10; with the leading '-', print all but the last NUM lines of each file
-q, --quiet, --silent    never print headers giving file names
-v, --verbose            always print headers giving file names
-z, --zero-terminated    line delimiter is NUL, not newline
    --help               display this help and exit
    --version            output version information and exit.

NUM may have a multiplier suffix:
b 512
kB 1000
K 1024
MB 1000*1000
M 1024*1024
GB 1000*1000*1000
G 1024*1024*1024
and so on for T, P, E, Z, Y.