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
follows.
- -r
- Generate random data instead of sequential data, the
default.
-
-b word
- Just print word repetitively.
-
-w word
- 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.
-
-s string
- Print data separated by string. Normally, newlines
separate data.
- -n
- Do not print the final newline normally appended to the
output.
-
-p precision
- 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.
The command
- 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)