35.18 Pasting Things in Columns

cut+paste	Do you ever wish you could paste two (or even three) files side by side? You can, if you have the System V paste program (or the public-domain implementation on the disc).

For example, to create a three-column file from files x , y , and z :

$ 

paste x y z > file

To make paste read standard input, use the - option, and repeat - for every column you want. For example, to make an old broken System V ls (which lists files in a single column) list files in four columns:

$ 

ls | paste - - - -

The "standard input" option is also handy when used with cut ( 35.14 ) . You can cut data from one position on a line and paste it back on another.

The separate data streams being merged are separated by default with a tab, but you can change this with the -d option. Unlike the -d option to cut , you need not specify a single character; instead, you can specify a list of characters, which will be used in a circular fashion. (I haven't figured a use for this - maybe you can.)

The characters in the list can be any regular character or the following escape sequences:

\n

newline

\t

tab

\\

backslash

\0

empty string

Use quoting ( 8.14 ) , if necessary, to protect characters from the shell.

There's also a -s option that lets you merge subsequent lines from one file. For example, to merge each pair of lines onto a single line:

$ 

paste -s -d"\t\n" list