Head

Command name:

    Head

Description:

    Displays the beginning of a file. By default, head will print the first 10 lines of the file.

syntax/structure:

    head [option] [file]

use case:

    To break down large files to make reading data easier. Head command allows us to modify the output and display the wanted amount of data. 

Options:

    -n or --lines 
    shows the specified number of lines 

    -c or --bytes
    shows the specified number of bytes

    -v or --verbose 
    show the file name tag

    -q or --quiet
    does not separate the content of multiple files with a file name tag

    -z, --zero-terminated
     line delimiter is NUL, not newline

    --help 
    display this help and exit

    --version
    output version information and exit

Examples:

    1. [user@host ~]$ head file_name // shows first ten lines of a file 

    2. [user@host ~]$ head -n[4] file_name // -n (4 lines) is used to change the number of 
    lines that are shown starting from the first line of the file

    3. [user@host ~]$ head -q file_name1 file_name2 // -q is used when reading the head of two 
    different files, this gives the output of both files together instead of separate

    4. [user@host ~]$ head file_name1 file_name2 // using the head command without the -q will
    display the files' output separately

    5. [user@host ~]$ head -c[20] file_name // using -c (number) is used to display 20
    bytes of a file

    6. [user@host ~]$ head -v file_name // using -v displays the file name followed by the first ten
    lines of the file 

    7. [user@host ~]$ head [option] file_name > ouput_file // this command can be used to 
    redirect output to desired folder. If the file does not already exist, it will create the new file

    8. [user@host ~]$ [command] | head [option] // the pipeline (|) command allow for a modified output of a command
    ex: [user@host ~]$ ls/etc | head // will print the first ten files in the etc directory