Grep is a command line application that is used to search a file or files and extract data from it/them according to a pattern or filter if you prefer. Grep stands for global regular-expression. There are many versions of grep available and regular expressions (for pattern matching) are available in most modern scripting languages such as ruby, python, perl, php, vb, etc. Grep, ngrep, egrep, etc. are available for multiple platforms including windows. They are well documented and can be downloaded for free.
PS -eaf|grep defunct
I think you mean the regular expression tool "grep".
Use the 'grep' command
The grep command is used to search for text, or lines containing certain words or strings of words. Stackoverflow, techonthenet, linux are a few sites that tell more about this command
For Unix, try the following: ls -1 | grep -v '^\.' | wc -l
Use the 'grep' family of commands to search for string pattern matches in multiple files.
Use the "-i" argument See 'man grep' for more information
Grep is: Global regular expression Parser
A Unix filter is a command pattern that allows the output of one command to be "piped" into the input of the next command. Commands like 'ls' which list a directory are not filters since they only generate output. Filter examples are grep, sed, sort, uniq, awk. Commands in Unix are usually filters unless they only create output, like 'ls', 'vi', etc.
i=1 while [ $i -le $# ] do grep -v Unix $i > $i done
You can use the application 'grep' to find words with specific letters. It comes with any standard unix installation such as Linux, or Mac OS X. There is a Windows version that can be found, as well.
egrep (or grep -E) allows the user to specify a pattern match using a regular expression pattern in the search. Regular expressions allow for a much wider search pattern, looking for patterns instead of just simple character sequences. The grep family of utilities is used to search for content within files that match a certain criteria.