coreutils: nproc invocation

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1 21.3 ‘nproc’: Print the number of available processors
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1 
1 Print the number of processing units available to the current process,
1 which may be less than the number of online processors.  If this
1 information is not accessible, then print the number of processors
1 installed.  If the ‘OMP_NUM_THREADS’ or ‘OMP_THREAD_LIMIT’ environment
1 variables are set, then they will determine the minimum and maximum
1 returned value respectively.  The result is guaranteed to be greater
1 than zero.  Synopsis:
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1      nproc [OPTION]
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11    The program accepts the following options.  Also see ⇒Common
 options.
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1 ‘--all’
1      Print the number of installed processors on the system, which may
1      be greater than the number online or available to the current
1      process.  The ‘OMP_NUM_THREADS’ or ‘OMP_THREAD_LIMIT’ environment
1      variables are not honored in this case.
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1 ‘--ignore=NUMBER’
1      If possible, exclude this NUMBER of processing units.
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1    An exit status of zero indicates success, and a nonzero value
1 indicates failure.
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