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342.

Read ARGs as input to the shell and execute the resulting command(s).

343.

Getopts is used by shell procedures to parse positional parameters.

OPTSTRING contains the option letters to be recognized; if a letter
is followed by a colon, the option is expected to have an argument,
which should be separated from it by white space.

Each time it is invoked, getopts will place the next option in the
shell variable $name, initializing name if it does not exist, and
the index of the next argument to be processed into the shell
variable OPTIND. OPTIND is initialized to 1 each time the shell or
a shell script is invoked. When an option requires an argument,
getopts places that argument into the shell variable OPTARG.

getopts reports errors in one of two ways. If the first character
of OPTSTRING is a colon, getopts uses silent error reporting. In
this mode, no error messages are printed. If an invalid option is
seen, getopts places the option character found into OPTARG. If a
required argument is not found, getopts places a ':' into NAME and
sets OPTARG to the option character found. If getopts is not in
silent mode, and an invalid option is seen, getopts places '?' into
NAME and unsets OPTARG. If a required argument is not found, a '?'
is placed in NAME, OPTARG is unset, and a diagnostic message is
printed.

If the shell variable OPTERR has the value 0, getopts disables the
printing of error messages, even if the first character of
OPTSTRING is not a colon. OPTERR has the value 1 by default.

Getopts normally parses the positional parameters ($0 - $9), but if
more arguments are given, they are parsed instead.

344.

Exec FILE, replacing this shell with the specified program.
If FILE is not specified, the redirections take effect in this
shell. If the first argument is `-l', then place a dash in the
zeroth arg passed to FILE, as login does. If the `-c' option
is supplied, FILE is executed with a null environment. The `-a'
option means to make set argv[0] of the executed process to NAME.
If the file cannot be executed and the shell is not interactive,
then the shell exits, unless the shell option `execfail' is set.

345.

Exit the shell with a status of N. If N is omitted, the exit status
is that of the last command executed.

346.

Logout of a login shell.

347.

fc is used to list or edit and re-execute commands from the history list.
FIRST and LAST can be numbers specifying the range, or FIRST can be a
string, which means the most recent command beginning with that
string.

-e ENAME selects which editor to use. Default is FCEDIT, then EDITOR,
then vi.

-l means list lines instead of editing.
-n means no line numbers listed.
-r means reverse the order of the lines (making it newest listed first).

With the `fc -s [pat=rep ...] [command]' format, the command is
re-executed after the substitution OLD=NEW is performed.

A useful alias to use with this is r='fc -s', so that typing `r cc'
runs the last command beginning with `cc' and typing `r' re-executes
the last command.

348.

Place JOB_SPEC in the foreground, and make it the current job. If
JOB_SPEC is not present, the shell's notion of the current job is
used.

349.

Place each JOB_SPEC in the background, as if it had been started with
`&'. If JOB_SPEC is not present, the shell's notion of the current
job is used.

350.

For each NAME, the full pathname of the command is determined and
remembered. If the -p option is supplied, PATHNAME is used as the
full pathname of NAME, and no path search is performed. The -r
option causes the shell to forget all remembered locations. The -d
option causes the shell to forget the remembered location of each NAME.
If the -t option is supplied the full pathname to which each NAME
corresponds is printed. If multiple NAME arguments are supplied with
-t, the NAME is printed before the hashed full pathname. The -l option
causes output to be displayed in a format that may be reused as input.
If no arguments are given, information about remembered commands is displayed.

351.

Display helpful information about builtin commands. If PATTERN is
specified, gives detailed help on all commands matching PATTERN,
otherwise a list of the builtins is printed. The -s option
restricts the output for each builtin command matching PATTERN to
a short usage synopsis.