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Full Discussion: SED * operator
Top Forums Shell Programming and Scripting SED * operator Post 302271163 by matrixmadhan on Wednesday 24th of December 2008 03:45:12 AM
Old 12-24-2008
Quote:
Originally Posted by sinpeak
Thanks to all for the replies.

To matrixmadhan :

Going by your reply -

"It should match zero or more characters in the character class [a-z]
it will match 'a', 'b', 'c' and not the next space character <' '> so just that part is replaced by 'X'"

I tried :-

echo "a 123 abc" | sed 's/[a-z]*/X/'
echo "ab 123 abc" | sed 's/[a-z]*/X/'
echo "abc 123 abc" | sed 's/[a-z]*/X/'

all gave the same output as : X 123 abc

From your reply and the above result I understand - "*" will always start checking from the left in the input string. If it does not find a match , 'X' is replaced at the very beginning of the input string and the job is done.

But if it does find a match , it ends trying to find another match AND 'X' is kept in place of the matched token/characters.

Would request you to please confirm/correct the above.

Thanks

It will check from the start of the string ( <left of the string> ) and I hope this is what you meant, right?

Rest, you are right.

You need to remember this * means match zero or more characters.

There is going to be a definite replacement of zero or more matching characters.
 

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LEARN ABOUT HPUX

fs_whereis

FS_WHEREIS(1)						       AFS Command Reference						     FS_WHEREIS(1)

NAME

       fs_whereis - Reports each file server housing a file or directory

SYNOPSIS

       fs whereis [-path <dir/file path>+] [-help]

       fs whe [-p <dir/file path>+] [-h]

DESCRIPTION

       The fs whereis command returns the name of each file server machine that houses the volume containing each directory or file named by the
       -path argument.

OPTIONS

       -path <dir/file path>+
	   Names each AFS file or directory for which to return the host file server machine. Partial pathnames are interpreted relative to the
	   current working directory, which is also the default value if this argument is omitted.

       -help
	   Prints the online help for this command. All other valid options are ignored.

OUTPUT

       The output includes a line for each specified directory or file. It names the file server machine on which the volume that houses the
       specified directory or file resides. A list of multiple machines indicates that the directory or file is in a replicated volume.

       Machine names usually have a suffix indicating their cell membership. If the cell is not clear, use the fs whichcell command to display the
       cell in which the directory or file resides. To display the cell membership of the local machine, use the fs wscell command.

EXAMPLES

       The following example indicates that volume housing the directory /afs/abc.com resides is replicated on both "fs1.abc.com" and
       "fs3.abc.com":

	  % fs whereis -path /afs/abc.com
	  File /afs/abc.com is on hosts fs1.abc.com fs3.abc.com

PRIVILEGE REQUIRED

       None

SEE ALSO

       fs_whichcell(1), fs_wscell(1)

COPYRIGHT

       IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

       This documentation is covered by the IBM Public License Version 1.0.  It was converted from HTML to POD by software written by Chas
       Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.

OpenAFS 							    2012-03-26							     FS_WHEREIS(1)
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