jot - print sequential or random data
The following options are available:
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 - or as an empty string. 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 a default of 1 or -1 if 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, the seed, s is picked randomly. The reps argument is expected to be an unsigned integer, and if given as zero is taken to be infinite. The begin and end arguments 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 arc4random(3) when no seed is specified, and through random(3) when a seed is given. When is asked to generate random integers or characters with begin and end values in the range of the random number generator function and no format is specified with one of the -w -b or -p options, will arrange for all the values in the range to appear in the output with an equal probability. In all other cases be careful to ensure that the output format's rounding or truncation will not skew the distribution of output values in an unintended way.
The name derives in part from iota a function in APL.
jot - 1 10
prints the integers from 1 to 10, while 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 step size, as in
jot - 9 0 -.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`
%[#][ ][{+,-}][0-9]*[.[0-9]*]?where ``?'' must be one of
[l]{d,i,o,u,x}or
{c,e,f,g,D,E,G,O,U,X}
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