SH-ARG(1)
NAME
arg − shell command-line argument parsing
SYNOPSIS
load arg
arg [ opts command ]... - args
DESCRIPTION
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.
EXAMPLE
The following shell script, script, takes options b, c and f, where f takes a file name argument. #!/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:
./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:
unknown option z ./script 1 0 file arguments are -bc
SOURCE
/appl/cmd/sh/arg.b