The pr command (Section 45.6) is famous for printing a file neatly on a page — with margins at top and bottom, filename, date, and page numbers. It can also print text in columns: one file per column or many columns for each file.
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.
The -m option reads
all files on the command line simultaneously and prints each in its own
column, like this:
% file1 file2 file3
The lines The lines The lines
of file1 of file2 of file3
are here are here are here
... ... ...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 -s
X option that sets the column separator to the
single character X.
By default, pr -m
doesn't put filenames in the heading. If you want that, use the
-h
option to make your own heading. Or maybe
you'd like to make a more descriptive heading. Here's an example using
process substitution to compare a directory with its RCS (Section
39.5) subdirectory:
% pr -m -h "working directory compared to RCS directory" <(ls) <(ls RCS)
2000-11-22 23:57 working directory compared to RCS directory Page 1
0001.sgm 0001.sgm,v
0002.sgm 0002.sgm,v
0007.sgm 0007.sgm,v
0008.sgm 0008.sgm,v
...(The heading comes from the GNU version of pr. Later examples in this article use a different version with a different heading format.)
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 -3 file1
Nov 1 19:44 1992 file1 Page 1
Line 1 here Line 57 here Line 115 here
Line 2 here Line 58 here Line 116 here
Line 3 here Line 59 here Line 117 here
... ... ...The columns aren't balanced — if the file will fit into one column, the
other columns aren't used. You can change that by adjusting
-l, the page length option; see the section
below.
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, like this?
% pr -l1 -t -3 file1
Line 1 here Line 2 here Line 3 here
Line 4 here Line 5 here Line 6 here
Line 7 here Line 8 here Line 9 here
... ... ...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. That's just what
you want if you want data in columns with no headings.
If you want headings too, pipe the output of pr through another pr:
% pr -l1 -t -3 file1 | pr -h file1
Nov 1 19:48 1992 file1 Page 1
Line 1 here Line 2 here Line 3 here
Line 4 here Line 5 here Line 6 here
Line 7 here Line 8 here Line 9 here
... ... ...The -h file1 puts the filename into the
heading.
Also see paste (Section 21.18). Of course, programming languages like awk (Section 20.10) and perl (Section 41.1) can also make text into columns.
— JP