| #!/bin/sh |
| # |
| # This script takes a filename as input and writes the current date to the |
| # file. If the file already exists, it will not be overwritten unless the '-f' |
| # (or '--force') flag is given. |
| # |
| # This script demonstrates several types of shFlags functionality. |
| # - declaration of the FLAGS_HELP variable to customize the help output |
| # - direct calling of the flags_help() function for script controlled usage |
| # output |
| # - handling of non-flag type command-line arguments that follow the flags |
| # |
| # Try the following: |
| # $ ./write_date.sh now.out |
| # $ cat now.out |
| # |
| # $ ./write_date.sh now.out |
| # $ cat now.out |
| # |
| # $ ./write_date.sh -f now.out |
| # $ cat now.out |
| |
| # source shflags |
| . ../src/shflags |
| |
| # configure shflags |
| DEFINE_boolean 'force' false 'force overwriting' 'f' |
| FLAGS_HELP="USAGE: $0 [flags] filename" |
| |
| |
| write_date() |
| { |
| date >"$1" |
| } |
| |
| die() |
| { |
| [ $# -gt 0 ] && echo "error: $@" >&2 |
| flags_help |
| exit 1 |
| } |
| |
| |
| # parse the command-line |
| FLAGS "$@" || exit 1 |
| eval set -- "${FLAGS_ARGV}" |
| |
| # check for filename |
| [ $# -gt 0 ] || die 'filename missing' |
| filename=$1 |
| |
| [ -f "${filename}" -a ${FLAGS_force} -eq ${FLAGS_FALSE} ] \ |
| && die 'filename exists; not overwriting' |
| write_date "${filename}" |