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Add 'examples/shell/shortcuts/getargs.sh'

master
Jakub Filo 9 months ago
parent
commit
546cd51b6d
  1. 56
      examples/shell/shortcuts/getargs.sh

56
examples/shell/shortcuts/getargs.sh

@ -0,0 +1,56 @@
#!/bin/sh
# POSIX
# Reset all variables that might be set
file=
verbose=0 # Variables to be evaluated as shell arithmetic should be initialized to a default or validated beforehand.
while :; do
case $1 in
-h|-\?|--help) # Call a "show_help" function to display a synopsis, then exit.
show_help
exit
;;
-f|--file) # Takes an option argument, ensuring it has been specified.
if [ -n "$2" ]; then
file=$2
shift
else
printf 'ERROR: "--file" requires a non-empty option argument.\n' >&2
exit 1
fi
;;
--file=?*)
file=${1#*=} # Delete everything up to "=" and assign the remainder.
;;
--file=) # Handle the case of an empty --file=
printf 'ERROR: "--file" requires a non-empty option argument.\n' >&2
exit 1
;;
-v|--verbose)
verbose=$((verbose + 1)) # Each -v argument adds 1 to verbosity.
;;
--) # End of all options.
shift
break
;;
-?*)
printf 'WARN: Unknown option (ignored): %s\n' "$1" >&2
;;
*) # Default case: If no more options then break out of the loop.
break
esac
shift
done
# if --file was provided, open it for writing, else duplicate stdout
if [ -n "$file" ]; then
exec 3> "$file"
else
exec 3>&1
fi
# Rest of the program here.
# If there are input files (for example) that follow the options, they
# will remain in the "$@" positional parameters.
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