http://manpages.ubuntu.com/manpages/trusty/man1/zgrep.1.html
NAME
Zgrep - search compressed files for a regular expression
SYNOPSIS
zgrep [options] <pattern> [files]
DESCRIPTION
Zgrep is a front end to the grep program that allows transparent search
on any combination of compressed and non-compressed files. If any given
file is compressed, its uncompressed content is used. If a given file
does not exist, and its name does not end with one of the known
extensions, zgrep tries the compressed file names corresponding to the
supported compressors. If no files are specified, data is read from
standard input, decompressed if needed, and fed to grep. Data read from
standard input must be of the same type; all uncompressed or all
compressed with the same compressor. The supported compressors are
bzip2, gzip, lzip and xz.
Exit status is 0 if match, 1 if no match, 2 if trouble.
OPTIONS
--help display this help and exit
-V, --version
output version information and exit
-a, --text
treat all files as text
-A, --after-context=<n>
print <n> lines of trailing context
-b, --byte-offset
print the byte offset of each line
-B, --before-context=<n>
print <n> lines of leading context
-c, --count
only print a count of matching lines per file
-C, --context=<n>
print <n> lines of output context
-e, --regexp=<pattern>
use <pattern> as the pattern to match
-E, --extended-regexp
<pattern> is an extended regular expression
-f, --file=<file>
obtain patterns from <file>
-F, --fixed-strings
<pattern> is a set of newline-separated strings
-h, --no-filename
suppress the prefixing filename on output
-H, --with-filename
print the filename for each match
-i, --ignore-case
ignore case distinctions
-I ignore binary files
-l, --files-with-matches
only print names of files containing matches
-L, --files-without-match
only print names of files containing no matches
-m, --max-count=<n>
stop after <n> matches
-n, --line-number
print the line number of each line
-o, --only-matching
show only the part of a line matching <pattern>
-q, --quiet
suppress all messages
-r, --recursive
operate recursively on directories
-s, --no-messages
suppress error messages
-v, --invert-match
select non-matching lines
--verbose
verbose mode (show error messages)
-w, --word-regexp
match only whole words
-x, --line-regexp
match only whole lines