Usage: gawk [POSIX or GNU style options] -f progfile [--] file ...
Usage: gawk [POSIX or GNU style options] [--] 'program' file ...
POSIX options:          GNU long options: (standard)
        -f progfile             --file=progfile
        -F fs                   --field-separator=fs
        -v var=val              --assign=var=val
Short options:          GNU long options: (extensions)
        -b                      --characters-as-bytes
        -c                      --traditional
        -C                      --copyright
        -d[file]                --dump-variables[=file]
        -D[file]                --debug[=file]
        -e 'program-text'       --source='program-text'
        -E file                 --exec=file
        -g                      --gen-pot
        -h                      --help
        -i includefile          --include=includefile
        -l library              --load=library
        -L[fatal|invalid]       --lint[=fatal|invalid]
        -M                      --bignum
        -N                      --use-lc-numeric
        -n                      --non-decimal-data
        -o[file]                --pretty-print[=file]
        -O                      --optimize
        -p[file]                --profile[=file]
        -P                      --posix
        -r                      --re-interval
        -s                      --no-optimize
        -S                      --sandbox
        -t                      --lint-old
        -V                      --version

To report bugs, see node `Bugs' in `'
which is section `Reporting Problems and Bugs' in the
printed version.  This same information may be found at
PLEASE do NOT try to report bugs by posting in comp.lang.awk.

gawk is a pattern scanning and processing language.
By default it reads standard input and writes standard output.

        gawk '{ sum += $1 }; END { print sum }' file
        gawk -F: '{ print $1 }' /etc/passwd