Here's the usage:
$ ./bgrep -h
below cmd output started 2018 Tue Apr 24 06:08:53 PM PDT
usage: bgrep [-e] [-b] [-A after_bytes] [-B before_bytes] [-o] pattern filelist
        -h              output this help message
        -e              echo pattern to stderr - for troubleshooting shell quoting issues
        -i              ignore case
        -f              flush frequently
        -b buffer_len   defines the buffer length
        -o overlap_size defines the amount of overlap between two buffers
        -l              list filenames along with the offsets
        -A num_bytes    number of bytes to display after the match.  Must include the match itself
        -B num_bytes    number of bytes to display before the match
        pattern         is an emacs-style regular expression
        filelist        is a list of filenames
    
See also bcgrep for a tool that can grep without fouling your buffer cache.
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