How to output the first part of files

How to output the first part of files

1. head name function in linux

head – output the first part of files

2. Synopsis of head command

head [OPTION]... [FILE]... 

3. Frequently used options for head command

-c, --bytes=[-]N
      print the first N bytes of each  file;  with  the
      leading  `-', print all but the last N bytes of
      each file
-n, --lines=[-]N
      print  the first N lines instead of the first 10;
      with the leading `-', print all but the last N
      lines of each file 

4. Examples of head command

Command head will by default print first 10 lines of a file. Lets prove it by creating test file from /etc/services which contains line numbers.

$ cat /etc/services | nl > /tmp/services.txt 

$ head /tmp/services.txt 

with -n option we can instruct head command to print line numbers.

$ head -n /tmp/services.txt 

make head command to print first 5 lines:

$ head -5 /tmp/services.txt 

Same as with option -n with option -c we can print out number of bytes to the standard output. Lets do small test:

$ wc -l -c services.txt
$ head -c 22173 /tmp/services.txt | wc -l