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Full Discussion: Reading of variable in a single line command
Top Forums Shell Programming and Scripting Reading of variable in a single line command Post 302758111 by Corona688 on Friday 18th of January 2013 12:53:11 PM
Old 01-18-2013
That is a useless use of cat and will prevent variables set inside the loop from being used outside the loop.

There is also no point using awk to split variables here when read can do that by itself.

There's also no point using awk 10,000 times to process 10,000 lines when awk can do that all at once. It's like making a hundred phonecalls to say a hundred individual words.

This should do the job with less fuss:

Code:
while IFS="|" read -r A B C D E
do
        echo "========="
        eval "$B"
done < inputfile

p.s.: The -r is probably necessary either way to read shell code. Without it, code containing backslash characters may be mangled.
Last edited by Corona688; 01-18-2013 at 02:03 PM..
 

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LEARN ABOUT OPENSOLARIS

ifparse

ifparse(1M)						  System Administration Commands					       ifparse(1M)

NAME

       ifparse - parse ifconfig command line

SYNOPSIS

       /sbin/ifparse [-fs] addr_family commands

DESCRIPTION

       Use  the  ifparse command to parse the ifconfig(1M) command line options and output substrings, one per line, as appropriate. If no options
       are specified, ifparse returns the entire ifconfig command line as a series of substrings, one per line.

OPTIONS

       The ifparse command supports the following options:

       -f    Lists only substrings of the ifconfig command line that are relevant to IP network multipath failover

       -s     Lists only substrings of the ifconfig command line that are not relevant to IP network multipath failover

OPERANDS

       The ifparse command does not support the interface operand of the ifconfig command.

EXAMPLES

       Example 1 Parsing Command Line Options Relevant to Failover

       The following example shows the use of the ifparse command to parse the command line options relevant to IP network multipath failover:

	 example# ifparse -f inet 1.2.3.4 up group one addif 1.2.3.5 -failover up
	 set 1.2.3.4 up

       Example 2 Parsing Command Line Options That Are Not Relevant to Failover

       The following example shows the use of the ifparse command to parse the command line options that are not relevant to IP network  multipath
       failover:

	 example# ifparse -s inet 1.2.3.4 up group one addif 1.2.3.5 -failover up
	 group one
	 addif 1.2.3.5 -failover up

       Example 3 Parsing the Command Line For All Options

       The following example shows the use of the ifparse command to parse the command line for all ifconfig options:

	 example# ifparse inet 1.2.3.4 up group one addif 1.2.3.5 -failover up
	 group one
	 set 1.2.3.4 up
	 addif 1.2.3.5 -failover up

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsr			   |
       +-----------------------------+-----------------------------+
       |Stability Level 	     |Obsolete			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ifconfig(1M), attributes(5)

DIAGNOSTICS

       usage: -fs <addr_family> <commands>
	   Description:

	   This message indicates an invalid command line.

       ifparse: Not enough space
	   Description:

	   This message indicates insufficient memory.

       ifparse: dhcp not supported for inet6
	   Description:

	   DHCP operations are not supported for the inet6 address family.

       ifparse: Operation <operation> not supported for <addr_family>
	   Description:

	   Most  operations  cannot  be used with all address families. For example, the broadcast operation is not supported on the inet6 address
	   family.

       ifparse: no argument for <operation>
	   Description:

	   Some operations, for example broadcast, require an argument.

NOTES

       The ifparse command is classified as an obsolete interface. It will likely be removed in a future release. You should not develop  applica-
       tions that depend upon this interface.

SunOS 5.11							    9 May 2001							       ifparse(1M)
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