Search file(s) for lines that match an extended expression (extended grep)
egrep [ options ] 'PATTERN' files ...
egrep is the same as `grep -E’
all other options are the same as grep
The PATTERN is a regexp. In typical usage, the regexp is quoted to prevent the shell from expanding any of the special characters as file name wildcards. Normally, `egrep’ prints the lines that matched.
If multiple file names are provided on the command line, each output line is preceded by the name of the file and a colon.
-c Print out a count of the lines that matched the pattern, instead of the lines themselves. -s Be silent. No output is produced, and the exit value indicates whether or not the pattern was matched. -v Invert the sense of the test. `egrep' prints the lines that do *not* match the pattern, and exits successfully if the pattern was not matched. -i Ignore case distinctions in both the pattern and the input data. -l Only print the names of the files that matched, not the lines that matched. -e PATTERN Use PATTERN as the regexp to match. The purpose of the `-e' option is to allow patterns that start with a `-'.