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Full Discussion: Bash : Parameter expansion ${var:-file*}
Top Forums Shell Programming and Scripting Bash : Parameter expansion ${var:-file*} Post 303039685 by popeye on Saturday 12th of October 2019 12:21:06 AM
Old 10-12-2019
Bash : Parameter expansion ${var:-file*}
Example data
Code:
$ ls *somehost*
10.10.10.10_somehost1.xyz.com.log  
11.11.11.11_somehost2.xyz.com.log

Code:
#!/bin/bash
#FILES="*.log"
FILES=${FILES:-*.log}

for x in $FILES
do
ip="${x%%_*}"     # isolate IP address
x="${x##*_}"       # isolate hostname
hnam="${x%.*}" # Remove the ".log" extension so that only the hostname.xyz.com remains
echo "$ip $hnam"

Output
Code:
10.10.10.10 somehost1.xyz.com
11.11.11.11 somehost2.xyz.com

Questions
1. Which is faster and more proper FILES="*.log" or FILES=${FILES:-*.log} or something else. There may be a very large number of files I would want to loop through.
2. How can I combine the last two parameter expansion statements : x="${x##*_}" and hnam="${x%.*}" without external calls.

Thanks in advance.
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LEARN ABOUT OPENDARWIN

nislog

nislog(1M)						  System Administration Commands						nislog(1M)

NAME

       nislog - display the contents of the NIS+ transaction log

SYNOPSIS

       /usr/sbin/nislog [-h num | -t num]  [-v] [directory...]

DESCRIPTION

       nislog  displays  the  contents of the NIS+ server transaction log on the standard output. This command can be used to track changes in the
       namespace. The /var/nis/trans.log file contains the transaction log maintained by the NIS+ server. When updates occur, they are	logged	to
       this  file  and	then  propagated  to replicas as log transactions.  When the log is checkpointed, updates that have been propagated to the
       replicas are removed.

       The nislog command can only be run on an NIS+ server by superuser. It displays the log entries for that server only.

       If directory is not specified, the entire log is searched. Otherwise, only those logs entries that correspond to the specified  directories
       are displayed.

OPTIONS

       -h num	       Display num transactions from the ``head'' of the log. If the numeric parameter is  0, only the log header is displayed.

       -t num	       Display	num transactions from the ``tail'' of the log. If the numeric parameter is  0, only the log header is displayed.

       -v	       Verbose mode.

FILES

       /var/nis/trans.log      transaction log

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWnisu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       nis+(1), rpc.nisd(1M), nisfiles(4), attributes(5)

NOTES

       NIS+  might  not  be  supported in future releases of the SolarisTM Operating Environment. Tools to aid the migration from NIS+ to LDAP are
       available in the Solaris 9 operating environment. For more information, visit http://www.sun.com/directory/nisplus/transition.html.

SunOS 5.10							    12 Dec 2001 							nislog(1M)
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