Bash 'pr' Command

Derived from Making Text in Columns with pr

pr <(ls ./) > out.txt

The -t option takes away the heading and margins at the top and bottom of each page. That's useful when "pasting" data into columns with no interruptions.

pr -t <(ls ./) > out.txt

The -m option reads all files on the command line simultaneously and prints each in its own column.

pr -m -t <(ls ./) > out.txt

pr may use TAB characters between columns. If that would be bad, you can pipe pr's output through expand. Many versions of pr have a -sX option that sets the column separator to the single character X.

pr -s' ' -m -t <(ls ./) > out.txt

By default, pr -m doesn't put filenames in the heading. If you want that, use the -h option to make your own heading.

pr -s' ' -h 'my heading' -m -t <(ls ./) > out.txt

One File, Several Columns: -number

An option that's a number will print a file in that number of columns. For instance, the -3 option prints a file in three columns. The file is read, line by line, until the first column is full (by default, that takes 56 lines). Next, the second column is filled. Then, the third column is filled. If there's more of the file, the first column of page 2 is filled -- and the cycle repeats

pr -s' ' -h 'my heading' -3 -t <(ls ./) > out.txt

Order Lines Across Columns: -l

Do you want to arrange your data across the columns, so that the first three lines print across the top of each column, the next three lines are the second in each column, and so on?

Use the -l1 (page length 1 line) and -t (no title) options. Each "page" will be filled by three lines (or however many columns you set). You have to use -t; otherwise, pr will silently ignore any page lengths that don't leave room for the header and footer.

pr -l1 -t -3 <(ls ./) > out.txt