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Full Discussion: cat -n and grep
Top Forums Shell Programming and Scripting cat -n and grep Post 302385668 by kapu on Saturday 9th of January 2010 02:35:10 AM
Old 01-09-2010
cat -n and grep
I am not sure if using cat -n is the most efficient way to split a file into multiple files, one file per line in the source file.
I thought using cat -n would make it easy to process the file because it produces an output that numbers each line that I could then grep for with the regex "^ *$i". But, I find it hard to reduce the output to be just the line number shown in $i. I am trying to add spaces after the variable to reduce the output. But that has the effect of producing no output.

Code:
i=6 && cat -n qso | egrep "^ *$i"
     6  vvv vvv vvv km2a km2a de a8dd. r r r tnx fer call kevin. name reggie. your rst is 569. rig is ic738 es running 50 watts. my antenna is a 4 el beam. i live in lansing, michigan. here, the weather is damp, temp is 50 f. been a ham for 10 years. during the day im a brewer. over to you kevin. km2a de a8dd+

i=6 && cat -n qso | egrep "^ *$i " produces nothing.

The file named qso contains multiple lines of text.
My goal is to parse qso and send each line to its own file using the naming convention qso(n) for the individual files. an example of the first two lines of qso follows:

vvv vvv vvv kq2k de w7ghl w7ghl. tnx ricky. ur rst is 456 456 wid qsb. name hr is jimmy. rig here is an icom ic
706ii with 400 watts. im using a 3 el yagi. the qth is boise, idaho. hr wx is a bit overcast, temp is 29 f. i w
ork as a beautician. been licenced since 1953. bk to you. kq2k de w7ghl+kn ^M
vvv vvv vvv a5ln/0 a5ln/0 a5ln/0 de w6os. thanks for the call pam. name jane. ur rst 367 367 with qrm. i live i
n oceanside oceanside, california. i have a ft2000 es running 500 watts. ant is g5rv. wx here is nice. ive been
a ham since 1907. i work hr as a policeman. back to you pam, 73 es cu agn. a5ln/0 de w6os *^M

My failed attempt to begin making a regex to parse follows:
i=1 && cat -n qso | egrep "^ *$i "

any time I add a space after $i in the regex, it no longer matches anything.
Last edited by kapu; 01-09-2010 at 04:16 AM..
 

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LEARN ABOUT POSIX

engine

ENGINE(1SSL)							      OpenSSL							      ENGINE(1SSL)

NAME

       openssl-engine, engine - load and query engines

SYNOPSIS

       openssl engine [ engine... ] [-v] [-vv] [-vvv] [-vvv] [-vvv] [-c] [-t] [-tt] [-pre command] [-post command] [ engine... ]

DESCRIPTION

       The engine command is used to query the status and capabilities of the specified engine's.  Engines may be specified before and after all
       other command-line flags.  Only those specified are queried.

OPTIONS

       -v -vv -vvv -vvvv
	   Provides information about each specified engine. The first flag lists all the possible run-time control commands; the second adds a
	   description of each command; the third adds the input flags, and the final option adds the internal input flags.

       -c  Lists the capabilities of each engine.

       -t  Tests if each specified engine is available, and displays the answer.

       -tt Displays an error trace for any unavailable engine.

       -pre command
       -post command
	   Command-line configuration of engines.  The -pre command is given to the engine before it is loaded and the -post command is given
	   after the engine is loaded.	The command is of the form cmd:val where cmd is the command, and val is the value for the command.  See
	   the example below.

EXAMPLE

       To list all the commands available to a dynamic engine:

	$ openssl engine -t -tt -vvvv dynamic
	(dynamic) Dynamic engine loading support
	     [ unavailable ]
	     SO_PATH: Specifies the path to the new ENGINE shared library
		  (input flags): STRING
	     NO_VCHECK: Specifies to continue even if version checking fails (boolean)
		  (input flags): NUMERIC
	     ID: Specifies an ENGINE id name for loading
		  (input flags): STRING
	     LIST_ADD: Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)
		  (input flags): NUMERIC
	     DIR_LOAD: Specifies whether to load from 'DIR_ADD' directories (0=no,1=yes,2=mandatory)
		  (input flags): NUMERIC
	     DIR_ADD: Adds a directory from which ENGINEs can be loaded
		  (input flags): STRING
	     LOAD: Load up the ENGINE specified by other settings
		  (input flags): NO_INPUT

       To list the capabilities of the rsax engine:

	$ openssl engine -c
	(rsax) RSAX engine support
	 [RSA]
	(dynamic) Dynamic engine loading support

ENVIRONMENT

       OPENSSL_ENGINES
	   The path to the engines directory.

SEE ALSO

       config(5)

COPYRIGHT

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       Licensed under the OpenSSL license (the "License").  You may not use this file except in compliance with the License.  You can obtain a
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1.1.1a								    2018-12-18							      ENGINE(1SSL)
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