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Full Discussion: Understanding awk 'expansion'
Top Forums Shell Programming and Scripting Understanding awk 'expansion' Post 302959250 by Scrutinizer on Friday 30th of October 2015 03:07:33 PM
Old 10-30-2015
Quote:
Originally Posted by cjcox
Code:
awk -v U=$(whoami) -F: '"/^" U "/" {print $6}' /etc/passwd

Hi, I do not think this will work. That evaluates to:
Code:
awk -F: '"/^username/"{print $6}' /etc/passwd

Which means if the string "/^username/" is true (i.e. non-empty) then print $6

So this always evaluates to true and it will print field 6 on every line..
 

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LEARN ABOUT CENTOS

cancel

cancel(1)																 cancel(1)

NAME

       cancel - cancel print request

SYNOPSIS

       cancel [ request-ID...] [destination...]

       cancel -u user... [destination...]

       The cancel utility cancels print requests. There are two forms of the cancel command.

       The first form of cancel has two optional arguments: print requests (request-ID) and destinations (destination). Specifying request-ID with
       destination cancels request-ID on destination. Specifying only the destination cancels the current print request on destination. If  desti-
       nation is not specified, cancel cancels the requested print request on all destinations.

       The second form of cancel cancels a user's print requests on specific destinations.

       Users  can  only  cancel  print	requests associated with their username. By default, users can only cancel print requests on the host from
       which the print request was submitted. If a super-user has set user-equivalence=true in /etc/printers.conf on the print server,	users  can
       cancel  print  requests	associated with their username on any host. Super-users can cancel print requests on the host from which the print
       request was submitted. Superusers can also cancel print requests from the print server.

       The print client commands locate destination information using the printers database in the  name  service  switch.  See  nsswitch.conf(4),
       printers(4), and printers.conf(4) for details.

       The following options are supported:

       -u user	       The name of the user for which print requests are to be cancelled. Specify user as a username.

       The following operands are supported:

       destination     The  destination  on which the print requests are to be canceled. destination is the name of a printer or class of printers
		       (see lpadmin(1M)). If destination is not specified, cancel cancels the requested print request on all destinations. Specify
		       destination  using atomic or POSIX-style (server:destination), names. See  for information regarding using POSIX-style des-
		       tination names with cancel. See standards(5) for information regarding POSIX.

       request-ID      The print request to be canceled. Specify request-ID using LP-style request IDs (destination-number).

       user	       The name of the user for which the print requests are to be cancelled. Specify user as a username.

       The following exit values are returned:

       0	       Successful completion.

       non-zero        An error occurred.

       /var/spool/print/*      LP print queue.

       $HOME/.printers	       User-configurable printer database.

       /etc/printers.conf      System printer configuration database.

       printers.conf.byname    NIS version of /etc/printers.conf.

       printers.org_dir        NIS+ version of /etc/printers.conf.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWpcu			   |
       +-----------------------------+-----------------------------+

       lp(1), lpq(1B), lpr(1B), lprm(1B), lpstat(1), lpadmin( 1M), nsswitch.conf(4), printers(4), printers.conf(4), attributes(5), standards(5)

       POSIX-style destination names (server:destination) are treated as print requests if destination has the same format as an LP-style request-
       ID. See standards(5).

       Some  print  servers send cancelation notification to job owners when their print jobs have been cancelled. This notification usually comes
       in the form of an email message. Cancelation notices cannot be disabled on a Solaris server.

								    23 Feb 2005 							 cancel(1)
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