Posts

Showing posts from March, 2008

Remove all empty directories

$ cleanlinks this is supported on few flavor of Linux (XFree86), you can use this script. #/bin/bash DIR="$1" [ -d $DIR ] && [ $(ls -l $DIR | wc -l) -eq 1 ] && rmdir $DIR || : $ script.sh dir1

Removing blank line from file

Using sed. $ sed '/^$/d' withblankline.txt > withoutblankline.txt Using grep. $ grep -v '^$' withblankline.txt > withoutblankline.txt Use following for loop (shell script) to remove all blank lines from all files stored in /home/prabhat/data directory: #!/bin/sh files="/home/prabhat/data/*.txt" for f in $files do sed '/^$/d' $i > $i.out mv $i.out $i done

How to check reverse DNS

The DNS is used to determine what IP address is associated with a given host name, so to reverse resolve a known IP address is to lookup what the associated host name for it. A reverse lookup is often referred to simply as reverse resolving, or more specifically reverse DNS lookups. Use of reverse DNS. Anti-spam Network troubleshooting Avoid spammers and phishers using a forward confirmed reverse DNS etc Check reverse DNS for given IP address under Linux or Windows XP/Server 2003. You can use standard UNIX / Linux utilities such as nslookup, dig or hosts to find out reverse DNS of a given IP address. eg; under Linux/UNIX/ $ host 66.65.123.34 or dig -x IP (66.65.123.34) and under Linux/UNIX/Windows nslookup 66.65.123.34