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seq
: Print numeric sequencesseq
prints a sequence of numbers to standard output. Synopses:
seq [option]… last seq [option]… first last seq [option]… first increment last
seq
prints the numbers from first to last by
increment. By default, each number is printed on a separate line.
When increment is not specified, it defaults to ‘1’,
even when first is larger than last.
first also defaults to ‘1’. So seq 1
prints
‘1’, but seq 0
and seq 10 5
produce no output.
The sequence of numbers ends when the sum of the current number and
increment would become greater than last,
so seq 1 10 10
only produces ‘1’.
increment must not be ‘0’; use the tool yes
to get
repeated output of a constant number.
first, increment and last must not be NaN
,
but inf
is supported.
Floating-point numbers may be specified in either the current or
the C locale. See Floating point.
The program accepts the following options. Also see Common options. Options must precede operands.
Print all numbers using format. format must contain exactly one of the ‘printf’-style floating point conversion specifications ‘%a’, ‘%e’, ‘%f’, ‘%g’, ‘%A’, ‘%E’, ‘%F’, ‘%G’. The ‘%’ may be followed by zero or more flags taken from the set ‘-+#0 '’, then an optional width containing one or more digits, then an optional precision consisting of a ‘.’ followed by zero or more digits. format may also contain any number of ‘%%’ conversion specifications. All conversion specifications have the same meaning as with ‘printf’.
The default format is derived from first, step, and last. If these all use a fixed point decimal representation, the default format is ‘%.pf’, where p is the minimum precision that can represent the output numbers exactly. Otherwise, the default format is ‘%g’.
Separate numbers with string; default is a newline. The output always terminates with a newline.
Print all numbers with the same width, by padding with leading zeros. first, step, and last should all use a fixed point decimal representation. (To have other kinds of padding, use --format).
You can get finer-grained control over output with -f:
$ seq -f '(%9.2E)' -9e5 1.1e6 1.3e6 (-9.00E+05) ( 2.00E+05) ( 1.30E+06)
If you want hexadecimal integer output, you can use printf
to perform the conversion:
$ printf '%x\n' $(seq 1048575 1024 1050623) fffff 1003ff 1007ff
For very long lists of numbers, use xargs to avoid system limitations on the length of an argument list:
$ seq 1000000 | xargs printf '%x\n' | tail -n 3 f423e f423f f4240
To generate octal output, use the printf %o
format instead
of %x
.
On most systems, seq can produce whole-number output for values up to
at least 2^{53}. Larger integers are approximated. The details
differ depending on your floating-point implementation.
See Floating point. A common
case is that seq
works with integers through 2^{64},
and larger integers may not be numerically correct:
$ seq 50000000000000000000 2 50000000000000000004 50000000000000000000 50000000000000000000 50000000000000000004
However, note that when limited to non-negative whole numbers,
an increment of less than 200, and no format-specifying option,
seq can print arbitrarily large numbers.
Therefore seq inf
can be used to
generate an infinite sequence of numbers.
Be careful when using seq
with outlandish values: otherwise
you may see surprising results, as seq
uses floating point
internally. For example, on the x86 platform, where the internal
representation uses a 64-bit fraction, the command:
seq 1 0.0000000000000000001 1.0000000000000000009
outputs 1.0000000000000000007 twice and skips 1.0000000000000000008.
An exit status of zero indicates success, and a nonzero value indicates failure.
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