Scsh cheat sheet
Olin Shivers
November 1996

This cheat sheet is intentionally kept brief and minimalist.
It is intended to function as an ASCII-format reminder for the
full manual, not as the definition. It can be read using GNU Emacs's
outline mode.

It is also not entirely up-to-date. I'd appreciate getting updates from users.
-------------------------------------------------------------------------------

* High-level forms

Extended process form:
    (PF [REDIR1 ...])

Redirection:
    (<  [FDES] FILE-NAME)
    (>  [FDES] FILE-NAME)
    (<< [FDES] OBJECT)
    (=  FDES FDES/PORT)
    (-  FDES/PORT)
    stdports
Subforms are implicitly backquoted.

Process form:
    (| PF1 ...)				; pipeline
    (|+ CONNECT-LIST PF1 ...)		; complex pipeline
    (begin . BODY)			; Scheme form
    (epf . EPF)				; Embedded extended process form
    (PROG ARG1 ... ARGn)		; Exec a program
Subforms are implicitly backquoted.

Using process forms in Scheme:
    (exec-epf . EPF)	; Nuke the current process.
    (& . EPF)		; Fork process in background. Return proc object.
    (run . EPF)		; Run process. Return exit code.

    (& . EPF) = (fork (lambda () (exec-epf . EPF)))
    (run . EPF) = (wait (& . EPF))

Interfacing to subprocess I/O:
    (run/port . EPF) -> port
    (run/file . EPF) -> string
    (run/string . EPF) -> string
    (run/strings . EPF) -> string list
    (run/sexp . EPF) -> object
    (run/sexps . EPF) -> list

There are procedural equivalents for each of these, e.g., run/port* and
run/file*, that take thunk arguments for the subprocess.

(port->string PORT) -> string
    Read until EOF on PORT, return data as a string.

(port->string-list PORT) -> string list
    Repeatedly apply READ-LINE to PORT until EOF. Return list of lines read.

(port->sexp-list PORT) -> list
    Repeatedly apply READ to PORT until EOF. Return list of items read.

(port->list READER PORT)
    Repeatedly apply READER to PORT until EOF. Return list of items read.

(reduce-port PORT READER OP . SEEDS)
    Evaluate (OP (READER PORT) . SEEDS) to get a new set of seeds
    (OP must return as many values as there are SEEDS). When
    a port read returns EOF, the current set of seed values are
    returned as multiple values.

(run/port+proc  . EPF) -> [port proc]
(run/port+proc* THUNK) -> [port proc]

(run/collecting  FDS . EPF) -> [port ...]
(run/collecting* FDS THUNK) -> [port ...]
    RUN/COLLECTING implicitly backquotes FDS.

(|| PF1 ... PFn)
(&& PF1 ... PFn)
    Conditionally execute processes.

(char-filter   filter) -> procedure
(string-filter filter [buflen]) -> procedure

* System calls

** Errors

(errno-error errno SYSCALL . DATA)
(with-errno-handler* HANDLER THUNK) -> value of thunk
    HANDLER is called on two arguments: (HANDLER ERRNO PACKET)
    where PACKET is a list of the form (ERRNO-MSG SYSCALL . DATA)
    If HANDLER returns at all, the handler search continues upwards.

(with-errno-handler HANDLER-SPEC . BODY)
    HANDLER-SPEC is of the form
    	((ERRNO PACKET) CLAUSE ...)
    ERRNO and PACKET are variables bound to the errno error being raised.
    There are two forms for handler clauses:
    	((ERRNO ...) . BODY)
    	(else . BODY)
    ERRNO are expressions evaluating to errno integers.

** I/O
*** Port Manipulation
(close-after PORT CONSUMER) -> value(s) of consumer
(error-output-port) -> port

(with-current-input-port  port . body) -> value(s) of body
(with-current-output-port port . body) -> value(s) of body
(with-error-output-port   port . body) -> value(s) of body

(with-current-input-port*  port thunk) -> value(s) of thunk
(with-current-output-port* port thunk) -> value(s) of thunk
(with-error-output-port*   port thunk) -> value(s) of thunk

(close fd/port)

(stdports->stdio)
(stdio->stdports)

(with-stdio-ports* thunk) -> value(s) of thunk
(with-stdio-ports . body) -> value(s) of body

(make-string-input-port) -> port
(string-output-port-output port) -> port
(call-with-string-output-port proc) -> str

** Port and file descriptors
(fdes->inport  fd) -> port
(fdes->outport fd) -> port
(port->fdes port)  -> fixnum
    Increment port's revealed count.

(port-revealed port) -> integer or #f
(release-port-handle port)
(call/fdes fd/port consumer) -> value(s) of consumer

(move->fdes fd/port target-fd) -> port or fdes

** Unix I/O

(dup fd/port [newfd]) 	    	-> fd/port
(dup->inport fd/port [newfd]) 	-> port
(dup->outport fd/port [newfd]) 	-> port
(dup->fdes fd/port [newfd]) 	-> fd

(file-seek fd/port offset whence)

(open-file fname flags [perms]) -> port
(open-input-file fname [flags]) -> port
(open-output-file fname [flags perms]) -> port
(open-fdes fname flags [perms]) -> integer

(fdes-flags fd/port)
(set-fdes-flags fd/port flags)
    Only Posix flag defined is FDFLAGS/CLOSE-ON-EXEC, which you should
    not ever have to use -- scsh manages this automatically.

(fdes-status fd/port)
(set-fdes-flags fd/port flags)

    Operations allowed	Flags
    ------------------	-----
    Open+get+set	open/append, open/non-blocking
			open/async, open/fsync (non-Posix)

    Open+get		open/read, open/write, open/read+write
			open/access-mask

    Open only		open/create, open/exclusive, 
			open/no-control-tty, open/truncate

(pipe) -> [rport wport]
(read-line [fd/port retain-newline?]) -> string or eof-object

(read-string nbytes [fd/port]) -> string or #f
(read-string! str [fd/port start end]) -> [nread or #f]
(read-string/partial nbytes [fd/port]) -> string or #f
(read-string!/partial str [fd/port start end]) -> [nread or #f]

(write-string string [fd/port start end])
(write-string/partial string [fd/port start end]) -> nwritten
(force-output [fd/port])

** File locking
(define-record lock-region
  exclusive?	; write or read lock?
  start		; integer: start, end & whence
  end           ; integer: define the region being locked.
  whence	; The value of SEEK/SET, SEEK/DELTA, or SEEK/END.
  proc)		; A proc object for the process locking the region.

(make-lock-region exclusive? start len [whence]) -> lock-region
    WHENCE defaults to the value of SEEK/SET.

(lock-region fdes lock)
(lock-region/no-block fdes lock)

(get-lock-region fdes lock) -> lock-region or #f

(unlock-region fdes lock)

(with-region-lock* fdes lock thunk)
(with-region-lock fdes lock body ...)	Syntax

** File system
(create-directory fname [perms override?])
(create-fifo fname [perms override?])
(create-hard-link oldname newname [override?])
    OVERRIDE? one of {#f, QUERY, other true value}

(delete-directory fname)
(delete-file fname)
(delete-filesys-object fname)

(read-symlink fname) -> string

(rename-file old-fname new-fname [override?])

(set-file-mode  fname/fd/port mode)
(set-file-owner fname/fd/port uid)
(set-file-group fname/fd/port gid)

(sync-file fd/port)
(sync-file-system)

(truncate-file fname/fd/port len)

(file-attributes fname/fd/port [chase?]) -> file-info

(define-record file-info
  type      ; {block-special, char-special, directory,
            ;     fifo, regular, socket, symlink}
  device    ; Device file resides on.
  inode     ; File's inode.
  mode      ; File's permission bits.
  nlinks    ; Number of hard links to this file.
  uid       ; Owner of file.
  gid       ; File's group id.
  size      ; Size of file, in bytes.
  atime     ; Last access time.
  mtime     ; Last status-change time.
  ctime)    ; Creation time.

Derived procedures:
    file-type           	 type 
    file-inode          	 inode 
    file-mode           	 mode 
    file-nlinks         	 nlinks 
    file-owner          	 uid 
    file-group          	 gid 
    file-size           	 size 
    file-last-access    	 atime 
    file-last-mod       	 mtime 
    file-last-status-change  	 ctime

(file-not-readable?   fname) -> boolean
(file-not-writable?   fname) -> boolean
(file-not-executable? fname) -> boolean

    Returns one of
        #f	               Access permitted
        SEARCH-DENIED 	       Can't stat---a protected directory
                               is blocking access.
        PERMISSION             Permission denied.
        NO-DIRECTORY           Some directory doesn't exist.
        NONEXISTENT            File doesn't exist.

(file-readable? fname) 	 -> boolean
(file-writable? fname)   -> boolean
(file-executable? fname) -> boolean

(file-not-exists? fname [chase?]) -> boolean
    #f              Exists.
    SEARCH-DENIED   Some protected directory
                    is blocking the search.
    #t              Doesn't exist.

(file-exists? fname [chase?]) -> boolean

(directory-files [dir dotfiles?]) -> string list
(glob pat1 ...) -> string list
(glob-quote string) -> string
(file-match root dot-files? pat1 ...) -> string list

(create-temp-file [prefix]) -> string
(temp-file-iterate maker [template]) -> [object ...]
    TEMPLATE defaults to the value of *TEMP-FILE-TEMPLATE*.

(temp-file-channel) -> [inport outport]

** Processes
(exec prog arg1 ...)
(exec-path prog arg1 ...)
(exec/env prog env arg1 ...)
(exec-path/env prog env arg1 ...)

(%exec prog arglist env)
(exec-path-search fname pathlist) -> string

(exit [status])
(%exit [status])

(suspend)

(fork [thunk]) -> proc or #d
(%fork [thunk]) -> proc or #f

(fork/pipe  [thunk]) -> proc or #f
(%fork/pipe [thunk]) -> proc or #f

(fork/pipe+  conns [thunk]) proc or #f
(%fork/pipe+ conns [thunk]) proc or #f

(wait proc/pid [flags]) ->  status [proc]

(call-terminally thunk)

** Process state

(umask) -> fixnum
(set-umask perms)
(with-umask* perms thunk) -> values of thunk
(with-umask perms . body) -> values of body

(chdir [fname])
(cwd) -> string
(with-cwd* fname thunk) -> value(s) of thunk
(with-cwd fname . body) -> value(s) of body

(pid) -> fixnum
(parent-pid) -> fixnum
(process-group) -> fixnum
(set-process-group [proc/pid] pgrp)

(user-login-name) -> string
(user-uid) -> fixnum 
(user-effective-uid) -> fixnum
(user-gid) -> fixnum
(user-effective-gid) -> fixnum
(user-supplementary-gids) -> fixnum list
(set-uid uid)
(set-gid gid)

(process-times) -> [ucpu scpu uchildren schildren]

** User and group db access

(user-info uid-or-name) -> user-info

(define-record user-info
    name
    uid
    gid
    home-dir
    shell)

(->uid uid/name) -> fixnum
(->username uid/name) -> string

(group-info gid-or-name) -> record

(define-record group-info
    name
    gid
    members)	; List of uids

(->gid gid/name) -> fixnum
(->group gid/name) -> string

** Accessing command-line arguments

command-line-arguments
    Does not include program name

(command-line) -> string list
    Includes program name in list.

(arg  arglist n [default])	    -> string
(arg* arglist n [default-thunk])    -> string
(argv n [default]) 		    -> string    
    ARG  is 1-based access to ARGLIST
    ARGV is 0-based access to prog + args

** System parameters

(system-name) -> string

** Signal system

(signal-process proc/pid sig)
(signal-procgroup prgrp sig)
(pause-until-interrupt)
(sleep secs)

Non-signal S48 interrupts
-------------------------
interrupt/memory-shortage

Posix signals with S48 interrupts
------------------------------
signal/alrm	interrupt/alrm  (aka interrupt/alarm)
signal/int  	interrupt/int   (aka interrupt/int)
signal/chld	interrupt/chld  
signal/cont	interrupt/cont  
signal/hup	interrupt/hup   
signal/quit	interrupt/quit  
signal/term	interrupt/term  
signal/tstp	interrupt/tstp  
signal/usr1	interrupt/usr1  
signal/usr2	interrupt/usr2  

signal/info	interrupt/info		Non-Posix
signal/io	interrupt/io		Non-Posix
signal/poll	interrupt/poll		Non-Posix
signal/prof	interrupt/prof		Non-Posix
signal/pwr	interrupt/pwr		Non-Posix
signal/urg	interrupt/urg		Non-Posix
signal/vtalrm	interrupt/vtalrm	Non-Posix
signal/winch	interrupt/winch		Non-Posix
signal/xcpu	interrupt/xcpu		Non-Posix
signal/xfsz	interrupt/xfsz		Non-Posix

Synchronous and uncatchable signals
-----------------------------------
signal/stop	Uncatchable Posix
signal/kill	Uncatchable Posix

signal/abrt	Synchronous Posix
signal/fpe	Synchronous Posix
signal/ill	Synchronous Posix
signal/pipe	Synchronous Posix
signal/segv	Synchronous Posix
signal/ttin	Synchronous Posix
signal/ttou	Synchronous Posix
		
signal/bus	Synchronous BSD + SVR4
signal/emt	Synchronous BSD + SVR4
signal/iot	Synchronous BSD + SVR4
signal/sys	Synchronous BSD + SVR4
signal/trap	Synchronous BSD + SVR4

** Interrupt handlers
(signal->interrupt sig) -> interrupt
(interrupt-set integer1 ...) -> integer

(enabled-interrupts) -> integer
(set-enabled-interrupts! integer) -> integer

(with-enabled-interrupts interrupt-set body ...)	Syntax
(with-enabled-interrupts* interrupt-set thunk)

(set-interrupt-handler! interrupt handler) -> old-handler
(interrupt-handler interrupt) -> handler
    HANDLER is #f (ignored), #t (default), or (lambda (enabled-ints) ...) proc.

** Time

(define-record date
  seconds minute hour month-day month year
  tz-name tz-secs summer?
  week-day year-day)

(make-date sec min hour mday month year [tz-name tz-secs summer? wday yday])

(time+ticks)
(ticks/sec)

(date [time tz])
(time [date])

(date->string date)
(format-date fmt date)

** Environment variables

(setenv var val)
(getenv var) -> string

(env->alist) -> string->string alist
(alist->env alist)

(alist-delete key alist)     -> alist
(alist-update key val alist) -> alist
(alist-compress alist) -> alist

(with-env* env-alist-delta thunk) -> value(s) of thunk
(with-total-env* env-alist thunk) -> value(s) of thunk

(with-env env-alist-delta . body) -> value(s) of body
(with-total-env env-alist . body) -> value(s) of body

(add-before elt before list) -> list
(add-after elt after list) -> list

** $USER $HOME, and $PATH

home-directory
exec-path-list

* Networking

** High Level Socket Routines 

*** clients
(socket-connect protocol-family/internet socket-type name port) -> socket
(socket-connect protocol-family/unix socket-type pathname) -> socket

*** server
(bind-listen-accept-loop protocol-family/internet proc port) -> does-not-return
(bind-listen-accept-loop protocol-family/unix proc pathname) -> does-not-return

proc is a procedure of two arguments: a socket and a socket-address

** Sockets
(create-socket protocol-family type [protocol]) -> socket
(create-socket-pair type) -> [socket1 socket2]
(close-socket socket) -> undefined

protocol-family/unix
protocol-family/internet

socket-type/stream
socket-type/datagram

for protocol see protocol-info

(define-record socket family inport outport)

** Socket Addresses
(define-record socket-address family)

(unix-address->socket-address pathname) -> socket-address
(internet-address->socket-address host-address service-port)-> socket-address

internet-address/any
internet-address/loopback
internet-address/broadcast

(socket-address->unix-address socket-address) -> pathname
(socket-address->internet-address socket-address) -> 
	[host-address service-port]

** Low Level Socket Routines

(connect-socket socket socket-address) -> undefined
(bind-socket socket socket-address) -> undefined
(listen-socket socket backlog) -> undefined
(accept-connection socket) -> [new-socket socket-address]

(socket-local-address socket) -> socket-address
(socket-remote-address socket) -> socket-address

(shutdown-socket socket how-to) -> undefined
how-to:
shutdown/receives
shutdown/sends
shutdown/sends+receives

** Socket Specific I/O
see read-string/write-string for info on arguments

(receive-message socket length [flags]) -> 
	[string-or-#f socket-address]
(receive-message! socket string [start] [end] [flags]) ->
	[count-or-#f  socket-address]
(receive-message/partial socket length [flags]) -> 
	[string-or-#f socket-address]
(receive-message!/partial socket string [start] [end] [flags]) ->
	[count-or-#f socket-address]

(send-message socket string [start] [end] [flags] [socket-address] ->
	undefined
(send-message/partial socket string [start] [end] [flags] [socket-address]) ->
	count

** Socket Options
(socket-option socket level option) -> value
(set-socket-option socket level option value) -> undefined

boolean:
socket/debug
socket/accept-connect
socket/reuse-address
socket/keep-alive
socket/dont-route
socket/broadcast
socket/use-loop-back
socket/oob-inline
socket/use-privileged
socket/cant-signal
tcp/no-delay

value:
socket/send-buffer
socket/receive-buffer
socket/send-low-water
socket/receive-low-water
socket/error
socket/type
ip/time-to-live
tcp/max-segment

socket/linger is #f or integer seconds

real number with microsecond resolution:
socket/send-timeout 
socket/receive-timeout


** Database-information entries

(host-info name-or-socket-address) -> host-info
(network-info name-or-socket-address) -> network-info
(service-info name-or-number [protocol-name]) -> service-info
(protocol-info name-or-number) -> protocol-info

(define-record host-info name aliases addresses)
(define-record network-info name aliases net) 
(define-record service-info name aliases port protocol)
(define-record protocol-info name aliases number)

* String manipulation

** Regular expressions

(string-match regexp string [start]) -> match or false
(regexp-match obj) -> boolean
(match:start match [match-number]) -> fixnum
(match:end match [match-number]) -> fixnum
(match:substring match [match-number]) -> string
(make-regexp str) -> re
(regexp? obj) -> boolean
(regexp-exec regexp str [start]) -> match or false
(regexp-quote str) -> string

** Other string manipulation facilities

(index string char [start]) -> fixnum or false
(rindex string char [start]) -> fixnum or false

(substitute-env-vars fname) -> string

** Manipulating file-names

** Record I/O and field parsing

(read-delimited  char-set [port]) -> string or eof
(read-delimited! char-set buf [port start end]) -> nchars or #f or eof

((record-reader [delims elide-delims? handle-delim]) [port]) -> string or eof
    HANDLE-DELIM one of {trim, split, concat}

(read-paragraph [port delimiter?])

** Parsing fields

(field-splitter  [regexp num-fields])                    -> parser
(infix-splitter  [delim  num-fields handle-delim])       -> parser
(suffix-splitter [delim  num-fields handle-delim])       -> parser
(sloppy-suffix-splitter [delim num-fields handle-delim]) -> parser
    Where (parser string [start])
    HANDLE-DELIM one of {trim, concat, split}

(join-strings strings [delimiter grammar])
    GRAMMAR one of {infix, suffix}

** Field readers

(field-reader [field-parser record-reader])
    
* Awk

(awk <reader-exp> <rec&field-vars> [<rec-counter>] <state-var-inits>
    <clause>
      .
      .
       )

* Miscellaneous routines

** Integer bitwise ops

(arithmetic-shift i j) -> integer
(bitwise-and i j) -> integer
(bitwise-ior i j) -> integer
(bitwise-not i) -> integer
(bitwise-xor i j) -> integer

** ASCII encoding

(char->ascii \character) -> integer
(ascii->char \integer) -> character

** Top level

(repl)

* Running scsh

scsh [meta-arg] [switch1 ...] [end-option arg1 ...]
    meta-arg: \ <script-file-name>

    switch: -e <entry-point>	Top-level entry point
	    -o <structure>	Open structure in current package.
	    -m <structure>	Switch to package.
	    -n <new-package>	Switch to new package.
	    
	    -lm <module> <file-name>	Load module into config package.
	    -l <file-name>		Load file into current package.
	    -dm				Do script module.
	    -ds				Do script.

    end-option:	-s <script>		Specifies script to load.
		-sfd <num>		Script from file descriptor <num>.
		-c <expression>		Eval <expression> and exit.
    	    	--

scshvm [meta-arg] [vm-options] [end-option arg1 ...]
    meta-arg: \ <fname>

    vm-options: -h heap-size
    	    	-s stack-size
    	    	-o object-file

    end-option:	-i image-file
    	    	--
(dump-scsh-program main fname)

** File locations
/usr/local/bin/scsh

/usr/local/lib/scsh/
    scshvm
    scsh
    scsh.image
    doc/

