w := new(tabwriter.Writer)

// Format in tab-separated columns with a tab stop of 8.

w.Init(os.Stdout, 0, 8, 0, '\t', 0)

fmt.Fprintln(w, "a\tb\tc\td\t.")

fmt.Fprintln(w, "123\t12345\t1234567\t123456789\t.")

fmt.Fprintln(w)

w.Flush()

// Format right-aligned in space-separated columns of minimal width 5

// and at least one blank of padding (so wider column entries do not

// touch each other).

w.Init(os.Stdout, 5, 0, 1, ' ', tabwriter.AlignRight)

fmt.Fprintln(w, "a\tb\tc\td\t.")

fmt.Fprintln(w, "123\t12345\t1234567\t123456789\t.")

fmt.Fprintln(w)

w.Flush()

// output:

// a b c d .

// 123 12345 1234567 123456789 .

//

// a b c d.

// 123 12345 1234567 123456789.

// Observe how the b's and the d's, despite appearing in the

// second cell of each line, belong to different columns.

w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, '.', tabwriter.AlignRight|tabwriter.Debug)

fmt.Fprintln(w, "a\tb\tc")

fmt.Fprintln(w, "aa\tbb\tcc")

fmt.Fprintln(w, "aaa\t") // trailing tab

fmt.Fprintln(w, "aaaa\tdddd\teeee")

w.Flush()

// output:

// ....a|..b|c

// ...aa|.bb|cc

// ..aaa|

// .aaaa|.dddd|eeee

// Observe that the third line has no trailing tab,

// so its final cell is not part of an aligned column.

const padding = 3

w := tabwriter.NewWriter(os.Stdout, 0, 0, padding, '-', tabwriter.AlignRight|tabwriter.Debug)

fmt.Fprintln(w, "a\tb\taligned\t")

fmt.Fprintln(w, "aa\tbb\taligned\t")

fmt.Fprintln(w, "aaa\tbbb\tunaligned") // no trailing tab

fmt.Fprintln(w, "aaaa\tbbbb\taligned\t")

w.Flush()

// output:

// ------a|------b|---aligned|

// -----aa|-----bb|---aligned|

// ----aaa|----bbb|unaligned

// ---aaaa|---bbbb|---aligned|