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Annotation of coherent/a/usr/man/COHERENT/namedpipe, revision 1.1.1.1

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                      3: named pipe                  Definition                 named pipe
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                      8: A  _n_a_m_e_d  _p_i_p_e  is  a  special  file  created  with  the  command
                      9: /eettcc/mmkknnoodd. Unlike the block- and character-special files created
                     10: by mmkknnoodd, a named pipe is not a device.
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                     12: A named pipe acts like a conventional pipe set up between related
                     13: processes.  It differs in that it  has a visible name that can be
                     14: seen  in  a  file  system.   It  also  differs  in  that  it  has
                     15: permissions (since it's a file and has a name) associated with it
                     16: just  like  any other  file.   This  allows a  named  pipe to  be
                     17: accessed by processes that are _n_o_t related to each other, and can
                     18: even  be  used  for  processes  that  are running  on  behalf  of
                     19: difference users.
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                     21: The following  illustrates how one process can  write data into a
                     22: named pipe and an unrelated process can read from it:
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                     24: 
                     25:      /etc/mknod my_pipe p     # create the named pipe
                     26:      chmod 644 my_pipe
                     27:      ls -lR / > my_pipe &     # pump data into pipe in background
                     28:      mail fred < my_pipe      # read from the pipe and process
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                     31: This script  creates a named  pipe called mmyy_ppiippee  and makes sure
                     32: that it is  readable; it then pumps a mass  of data into the pipe
                     33: (in the  background), and then  has a process read  data from the
                     34: named pipe  and perform some  action on them (in  this case, mail
                     35: the data  to use ffrreedd).  In this example,  the mmaaiill process could
                     36: be  running from  some other  login  and could  either be  in the
                     37: foreground or background.
                     38: 
                     39: ***** See Also *****
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                     41: ddeeffiinniittiioonnss, mmkknnoodd, ppiippee
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                     64: COHERENT Lexicon                                           Page 1
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