zgrep - search possibly compressed files for a regular expression
zgrep [ grep_options ] [-e]patternfilename...
Zgrep invokes grep on compressed or gzipped files. All options specified are passed directly to grep. If no file is specified, then
the standard input is decompressed if necessary and fed to grep. Otherwise the given files are uncompressed if necessary and fed to
If the GREP environment variable is set, zgrep uses it as the grep program to be invoked.