jot - print sequential or random data
jot [ options ] [ reps [ begin [ end [ s ] ] ] ]
Jot is used to print out increasing, decreasing, random, or redundant
data, usually numbers, one per line. The options are understood as
-r Generate random data instead of sequential data, the default.
Just print word repetitively.
Print word with the generated data appended to it. Octal,
hexadecimal, exponential, ASCII, zero padded, and right-adjusted
representations are possible by using the appropriate printf(3)
conversion specification inside word, in which case the data are
inserted rather than appended.
-c This is an abbreviation for -w %c.
Print data separated by string. Normally, newlines separate
-n Do not print the final newline normally appended to the output.
Print only as many digits or characters of the data as indicated
by the integer precision. In the absence of -p, the precision
is the greater of the precisions of begin and end. The -p
option is overridden by whatever appears in a printf(3)
conversion following -w.
The last four arguments indicate, respectively, the number of data, the
lower bound, the upper bound, and the step size or, for random data,
the seed. While at least one of them must appear, any of the other
three may be omitted, and will be considered as such if given as -.
Any three of these arguments determines the fourth. If four are
specified and the given and computed values of reps conflict, the lower
value is used. If fewer than three are specified, defaults are
assigned left to right, except for s, which assumes its default unless
both begin and end are given.
Defaults for the four arguments are, respectively, 100, 1, 100, and 1,
except that when random data are requested, s defaults to a seed
depending upon the time of day. Reps is expected to be an unsigned
integer, and if given as zero is taken to be infinite. Begin and end
may be given as real numbers or as characters representing the
corresponding value in ASCII. The last argument must be a real number.
Random numbers are obtained through random(3). The name jot derives in
part from iota, a function in APL.
jot 21 -1 1.00
prints 21 evenly spaced numbers increasing from -1 to 1. The ASCII
character set is generated with
jot -c 128 0
and the strings xaa through xaz with
jot -w xa%c 26 a
while 20 random 8-letter strings are produced with
jot -r -c 160 a z | rs -g 0 8
Infinitely many yes’s may be obtained through
jot -b yes 0
and thirty ed(1) substitution commands applying to lines 2, 7, 12, etc.
is the result of
jot -w %ds/old/new/ 30 2 - 5
The stuttering sequence 9, 9, 8, 8, 7, etc. can be produced by suitable
choice of precision and step size, as in
jot 0 9 - -.5
and a file containing exactly 1024 bytes is created with
jot -b x 512 > block
Finally, to set tabs four spaces apart starting from column 10 and
ending in column 132, use
expand -`jot -s, - 10 132 4`
and to print all lines 80 characters or longer,
grep `jot -s "" -b . 80`
ed(1), expand(1), rs(1), yes(1), printf(3), random(3), expand(1)