I need help with...<various> Post: 302228301

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Top Forums Shell Programming and Scripting I need help with...<various> Post 302228301 by era on Saturday 23rd of August 2008 08:47:04 PM

08-23-2008

Registered User

You can have as many commands as you like between the "do" and "done", and of course, they can be new loops with "do" and "done" in them. Not sure where you'd need that, though. You can simply modify the sed script to shuffle things around in a different order if that's how you like them.

Code:

sed "s/.*/IP for $host is & at $nameserver"

The "s/from/to/" command in sed will substitute the stuff in "from" with the stuff in "to" on each line. In this case we are replacing the IP address printed by dig with the longer string. & retrieves the "from" string into the "to" string. Dot star is the regular expression for "everything on this line" (dot means any character, star means any number of times).

Just to show an alternate way of doing it, here's a loop which prints the message piecemeal.

Code:

#!/bin/sh
host=$1
dig +short ns $host |
while read nameserver; do
  echo -n "IP for $host is "
  dig +short @$nameserver $host | tr '\n' ' '  # replace final newline with space
  echo "at $nameserver"
done

Or you can interpolate with backticks

Code:

  echo IP for $host is `dig +short @$nameserver $host` at $nameserver

Backticks AKA grave accents (ASCII 96) capture the output of one command so you can use it in the command line of another command. Notice that those are not regular single quotes. Copy/paste them if you can't find them on your keyboard.

Last edited by era; 08-23-2008 at 09:57 PM.. Reason: Show alternate way of coding it with echos to print the desired message

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LEARN ABOUT OPENSOLARIS

continue

break(1)							   User Commands							  break(1)

NAME

       break, continue - shell built-in functions to escape from or advance within a controlling while, for, foreach, or until loop

SYNOPSIS

   sh
       break [n]

       continue [n]

   csh
       break

       continue

   ksh
       *break [n]

       *continue [n]

   ksh93
       +break [n]

       +continue [n]

DESCRIPTION

   sh
       The break utility exits from the enclosing for or while loop, if any. If n is specified, break n levels.

       The continue utility resumes the next iteration of the enclosing for or while loop. If n is specified, resume at the n-th enclosing loop.

   csh
       The  break  utility  resumes  execution after the end of the nearest enclosing foreach or while loop. The remaining commands on the current
       line are executed. This allows multilevel breaks to be written as a list of break commands, all on one line.

       The continue utility continues execution of the next iteration of the nearest enclosing while or foreach loop.

   ksh
       The break utility exits from the enclosed for, while, until, or select loop, if any. If n is specified,	then  break  n	levels.  If  n	is
       greater than the number of enclosing loops, the outermost enclosing loop shall be exited.

       The  continue utility resumes the next iteration of the enclosed for, while, until, or select loop. If n is specified then resume at the n-
       th enclosed loop. If n is greater than the number of enclosing loops, the outermost enclosing loop shall be used.

       On this manual page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:

	   1.	  Variable assignment lists preceding the command remain in effect when the command completes.

	   2.	  I/O redirections are processed after variable assignments.

	   3.	  Errors cause a script that contains them to abort.

	   4.	  Words that follow a command preceded by ** that are in the format of a variable assignment are expanded with the same rules as a
		  variable  assignment.  This  means  that tilde substitution is performed after the = sign, and also that word splitting and file
		  name generation are not performed.

   ksh93
       break is a shell special built-in that exits the smallest enclosing for, select, while, or until loop. It also exits the nth enclosing loop
       if n is specified. Execution continues at the command following the loop or loops.

       If n is specified, it must be a positive integer >=1. If n is larger than the number of enclosing loops, the last enclosing loop is exited.

       continue  is  a	shell special built-in that continues execution at the top of the smallest enclosing for, select, while, or until loop, if
       any; or of the top of the nth enclosing loop if n is specified.

       If n is specified, it must be a positive integer >=1. If n is larger than the number of enclosing loops, the last enclosing loop is used.

       On this manual page, ksh93(1) commands that are preceded by one or two + symbols are special built-in commands and are treated the  follow-
       ing ways:

	   1.	  Variable assignment lists preceding the command remain in effect when the command completes.

	   2.	  I/O redirections are processed after variable assignments.

	   3.	  Errors cause a script that contains them to abort.

	   4.	  Built-in commands are not valid function names.

	   5.	  Words  following  a command preceded by ++ that are in the format of a variable assignment are expanded with rules as a variable
		  assignment. This means that tilde substitution is performed after the = sign and field splitting and file  name  generation  are
		  not performed.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       csh(1), exit(1), ksh(1), ksh93(1), sh(1), attributes(5)

SunOS 5.11							    8 Apr 2008								  break(1)