ROT(1)ROT(1)NAMErot - rotate a file
SYNOPSISrot [-rbloB] [-c c] [file]
DESCRIPTION
Rot rotates a file, so that lines become columns and vice versa. With‐
out any options, the file will be rotated clockwise. So, from the input
abcde
abcd
abc
ab
a
xx xx
A
AB
ABC
ABCD
ABCDE
you will get
AAAAA aaaaa
BBBB bbbb
CCC ccc
DD x dd
E x e
x
x
Rot uses a two pass algorithm, where the first part collects the line
length of each line in the input, and the second prints out the new
lines, seeking through the input file. When no file or - is given, rot
reads from standard input.
OPTIONS-r rotate reverse (counter-clockwise)
-b normally, rot suppresses printing of trailing blanks in output
lines. This option retains them, so all blanks of the input
will appear in the output
-l do only the first pass and print the number of lines and the
length of the longest line found to standard output
-o change order of columns; in combination with the rotation this
yields one more file operation (see below)
-B this is for big files; the data will be hold in temporary files
rather than in memory; this slows down rot enormously
-c c use c as "line"-separator, instead of the newline character
REMARKS
One may ask, what rot is useful for. Think about the functionality of
programs like cat(1), or the line oriented grep(1), cut(1), sed(1),
sort(1), and others, when applied to a rotated file. In conjunction
with rot they do not longer work on lines, but columns. For example
rot f | grep ... | rot-r
is a grep on columns of the file f.
The -o option permits you to manipulate a file in some way of "reflect‐
ing" it in a "diagonal" line. The following table shows the different
effects of rot called with various options. Data manipulation is shown
by means of the output of a file with the contents
AB
CD
and a symbolic notation. R means Rotation (angle given), M means
reflection at given mirror axis. Combinations of two calls of rot are
also given. (Other combinations have identical effects to one of the
mentioned.)
┌──────────────┬────────┬──────────┐
│call │ output │ function │
├──────────────┼────────┼──────────┤
│rot │ CA │ R │
│ │ DB │ -90 deg │
├──────────────┼────────┼──────────┤
│rot -r │ BD │ R │
│ │ AC │ 90 deg │
├──────────────┼────────┼──────────┤
│rot -o │ DB │ M │
│ │ CA │ / │
├──────────────┼────────┼──────────┤
│rot -ro │ AC │ M │
│ │ BD │ \ │
├──────────────┼────────┼──────────┤
│rot | rot │ DC │ R │
│ │ BA │ 180 deg │
├──────────────┼────────┼──────────┤
│rot | rot-r │ AB │ (Id) * │
│ │ CD │ │
├──────────────┼────────┼──────────┤
│rot | rot-o │ BA │ M ** │
│ │ DC │ | │
├──────────────┼────────┼──────────┤
│rot | rot-ro │ CD │ M │
│ │ AB │ - │
└──────────────┴────────┴──────────┘
* Note, that rot|rot -r (or rot|rot|rot|rot) is not exactly the
null operator. Rot must insert blanks to keep track of the columns.
They may appear at the end of lines in a further run of rot, if the -b
option is given. Without this option blanks from the original input
may be lost.
** This is not the same as what is done by rev(1). Rev does not retain
columns!
Rot knows nothing about tab characters, use expand(1) to handle them
correctly.
FILES
/tmp/rot* -
temporarily copied input, if standard input is incapable of
seeking (pipe or terminal) (-B option only)
/tmp/rod* -
tempfile for holding length of input lines (-B option only)
SEE ALSOrev(1), tail(1bsd), tac(1public), expand(1), colrm(1)AUTHOR
Martin Schmidt
Dortmund - W. Germany
mschmidt@exunido.uucp
UNIX public ROT(1)
