arg - shell command-line argument parsing load arg

arg [ opts command ]... - args

Arg is a loadable module for sh (1) that parses command-line arguments in the same form as arg (2). It accepts a list of ( opts , command ) pairs, where each character in opts is an acceptable option, and command is a shell command to be run if any character in opts is found. Any trailing plus ( + ) characters in opts cause arg to extract the same number of arguments associated with the option before running command . For the duration of command , the environment variable $opt will be set to the option that has been found, and $arg will be set to the option's arguments (if the correct number of arguments have been extracted; otherwise a message will be printed, and a usage exception raised). The option character asterisk ( * ) matches any option letter (this must be quoted, to avoid the usual special interpretation by the shell). Only one command will be run for any option found; if there is no matching option letter, then a default error message will be printed, and a usage exception raised.

The list of option specifications is terminated with a single minus ( - ); the arguments to be parsed follow this. When the argument parsing has finished the environment variable $* is set to the remaining list of arguments.

The following shell script, script , takes options b , c and f , where f takes a file name argument. .EX #!/dis/sh load arg bflag := cflag := 0 file := () args := $* (arg bc {$opt^flag = 1} f+ {file=$arg} r++++ {rect=$arg} '*' {echo unknown option $opt} - $args ) echo $0 $bflag $cflag $file echo rect $rect echo arguments are $*

When invoked as follows:

"script -bc -r 0 10 50 100 -ffile a b c"

the output is:

.EX ./script 1 1 file rect 0 10 50 100 arguments are a b c

and when invoked by:

"script -b -f file -z -- -bc"

the output is:

.EX unknown option z ./script 1 0 file arguments are -bc /appl/cmd/sh/arg.b sh (1), arg (2), sh-std (1)