UNIX PROGRAMMER'S MANUAL











                           K. Thompson



                          D. M. Ritchie









                        November 3, 1971



































































































                          INTRODUCTION





This manual gives complete descriptions of all the publicly

available features of UNIX.  It provides neither a general over-

view (see "The UNIX Time-sharing System" for that) nor details of

the implementation of the system (which remain to be disclosed).



Within the area it surveys, this manual attempts to be as com-

plete and timely as possible.  A conscious decision was made to

describe each program in exactly the state it was in at the time

its manual section was prepared.  In particular, the desire to

describe something as it should be, not as it is, was resisted.

Inevitably, this means that many sections will soon be out of

date.  (The rate of change of the system is so great that a dis-

mayingly large number of early sections had to be modified while

the rest were being written.  The unbounded effort required to

stay up-to-date is best indicated by the fact that several of the

programs described were written specifically to aid in prepara-

tion of this manual!)



This manual is divided into seven sections:



   I.   Commands

   II.  System calls

   III. Subroutines

   IV.  Special files

   V.   File formats

   VI.  User-maintained programs

   VII. Miscellaneous



Commands are programs intended to be invoked directly by the

user, in contradistinction to subroutines, which are intended to

be called by the user's programs.  Commands generally reside in

directory /bin (for binary programs).  This directory is searched

automatically by the command line interpreter.  Some programs

classified as commands are located elsewhere; this fact is indi-

cated in the appropriate sections.



System calls are entries into the UNIX supervisor.  In assembly

language, they are coded with the use of the opcode "sys", a syn-

onym for the trap instruction.



The special files section discusses the characteristics of each

system "file" which actually refers to an I/O device.



The file formats section documents the structure of particular

kinds of files; for example, the form of the output of the loader

and assembler is given.  Excluded are files used by only one com-

mand, for example the assembler's intermediate files.



User-maintained programs are not considered part of the UNIX sys-

tem, and the principal reason for listing them is o indicate

their existence without necessarily giving a complte description.

The author should be consulted for information.



The miscellaneous section gathers odds and ends.





Each section consists of a number of independent entries of a

page or so each.  The name of the entry is in the upper right

corner of its pages, its preparation date in the upper left.  En-

tries within each section are alphabetized.  It was thought bet-

ter to avoid running page numbers, since it is hoped that the

manual will be updated frequently.



All entries have a common format.



     The name section repeats the entry name and gives a very

     short description of its purpose.



     The synopsis summarizes the use of the program being de-

     scribed.  A few conventions are used, particularly in the

     Commands section:



        Underlined words are considered literals, and are typed

        just as they appear.



        Square brackets ([]) around an argument indicate that the

        argument is optional.  When an argument is given as

        "name", it always refers to a file name.



        Ellipses "..." are used to show that the previous

        argument-prototype may be repeated.



        A final convention is used by the commands themselves.

        An argument beginning with a minus sign "-" is often tak-

        en to mean some sort of flag argument even if it appears

        in a position where a file name could appear.  Therefore,

        it is unwise to have files whose names begin with "-".



     The description section discusses in detail the subject at

     hand.



     The files section gives the names of files which are built

     into the program.



     A see also section gives pointers to related information.



     A diagnostics section discusses the diagnostics that may be

     produced.  This section tends to be as terse as the diagnos-

     tics themselves.



     The bugs section gives known bugs and sometimes deficien-

     cies.  Occasionally also the suggested fix is described.



     The owner section gives the name of the person or persons to

     be consulted in case of difficulty.  The rule has been that

     the last one to modify something owns it, so the owner is

     not necessarily the author.  The owner's initials stand for:



        ken    K. Thompson

        dmr    D. M. Ritchie

        jfo    J. F. Ossanna

        rhm    R. Morris



     These three-character names also happen to be UNIX user

     ID's, so messages may be transmitted by the mail command or,

     if the addressee is logged in, by write.



At the beginning of this document is a table of contents, orga-

nized by section and alphabetically within each section.  There

is also a permuted index derived from the table of contents.

Within each index entry, the title of the writeup to which it

refers is followed by the appropriate section number in parenthe-

ses.  This fact is important because there is considerable name

duplication among the sections, arising principally from commands

which exist only to exercise a particular system call.





This manual was prepared using the UNIX text editor ed and the

formatting program roff.



































































































































                        TABLE OF CONTENTS



I.  COMMANDS



ar ........................... archive (combine) files

as ........................... assembler

b ............................ compile B program

bas .......................... BASIC dialect

bcd .......................... convert ASCII to BCD

boot ......................... reboot system

cat .......................... concatenate (or print) files

chdir ........................ change working directory

check ........................ check consistency of file system

chmod ........................ change access mode of files

chown ........................ change owner of files

cmp .......................... compare file contents

cp ........................... copy file

date ......................... get date and time of day

db ........................... symbolic debugger

dbppt ........................ write binary paper tape

dc ........................... desk calculator

df ........................... find free disk space

dsw .......................... delete files interactively

dtf .......................... format DECtape

du ........................... find disk usage

ed ........................... text editor

find ......................... find file with given name

for .......................... compile Fortran program

form ......................... generate form letter

hup .......................... hang up typewriter

lbppt ........................ read binary paper tape

ld ........................... link editor (loader)

ln ........................... link to file

ls ........................... list contents of directory

mail ......................... send mail to another user

mesg ......................... permit or deny messages

mkdir ........................ create directory

mkfs ......................... initialize file system

mount ........................ mount removable file system

mv ........................... move or rename file

nm ........................... print namelist

od ........................... octal dump of file

pr ........................... print file with headings

rew .......................... rewind DECtape

rkd .......................... dump disk to tape

rkf .......................... format RK disk

rkl .......................... load disk from tape

rm ........................... remove (delete) file

rmdir ........................ remove (delete) directory

roff ......................... format text for printing

sdate ........................ adjust date and time

sh ........................... command interpreter

stat ......................... get file status

strip ........................ remove symbols, relocation bits

su ........................... become super-user

sum .......................... sum file

tap .......................... manipulate DECtape

tm ........................... get time information

tty .......................... find name of terminal

type ......................... print file page-by-page

umount ....................... dismount removable file system

un ........................... find undefined symbols

wc ........................... get (English) word count

who .......................... who is on the system

write ........................ write to another user





II.  SYSTEM CALLS



break ........................ set program break

cemt ......................... catch EMT traps

chdir ........................ change working directory

chmod ........................ change mode of file

chown ........................ change owner of file

close ........................ close open file

creat ........................ create file

exec ......................... execute program file

exit ......................... terminate execution

fork ......................... create new process

fstat ........................ status of open file

getuid ....................... get user ID

gtty ......................... get typewriter mode

ilgins ....................... catch illegal instruction trap

intr ......................... catch or inhibit interrupts

link ......................... link to file

mkdir ........................ create directory

mount ........................ mount file system

open ......................... open file

quit ......................... catch or inhibit quits

read ......................... read file

rele ......................... release processor

seek ......................... move read or write pointer

setuid ....................... set user ID

smdate ....................... set date modified of file

stat ......................... get file status

stime ........................ set system time

stty ......................... set mode of typewriter

tell ......................... find read or write pointer

time ......................... get time of year

umount ....................... dismount file system

unlink ....................... remove (delete) file

wait ......................... wait for process

write ........................ write file





III.  SUBROUTINES



atof ......................... convert ASCII to floating

atoi ......................... convert ASCII to integer

ctime ........................ convert time to ASCII

exp .......................... exponential function

fptrap ....................... floating-point simulator

ftoa ......................... convert floating to ASCII

get .......................... get character

itoa ......................... convert integer to ASCII

log .......................... logarithm base e

mesg ......................... print string on typewriter

ptime ........................ print time

putc ......................... write character or word

sin .......................... sine, cosine

switch ....................... transfer depending on value





IV.  SPECIAL FILES



mem .......................... core memory as file

ppt .......................... punched paper tape

rf0 .......................... RF disk file

rk0 .......................... RK disk file

tap0,...,tap7 ................ DECtape file

tty .......................... console typewriter

tty0,...,tty5 ................ remote typewriter





V.  FILE FORMATS



a.out ........................ assembler and loader output

archive ...................... archive file

bppt ......................... binary paper tape format

core ......................... core image file

directory .................... directory format

file system .................. file system format

passwd ....................... password file

uids ......................... map names to user ID's

utmp ......................... logged-in user information





VI.  USER MAINTAINED PROGRAMS



basic ........................ DEC supplied BASIC

bj ........................... the game of blackjack

cal .......................... print calender

chess ........................ the game of chess

das .......................... disassembler

dli .......................... load DEC binary paper tapes

dpt .......................... read DEC ASCII paper tapes

moo .......................... the game of MOO

sort ......................... sort a file

ttt .......................... the game of tic-tac-toe





VII.  MISCELLANEOUS



as2 .......................... assembler's pass 2

ascii ........................ map of ASCII

ba ........................... B assembler

bc ........................... B compiler

bilib ........................ B interpreter library

bproc ........................ boot procedure

brt1,brt2 .................... B start and finish

f1,f2,f3,f4 .................. Fortran compiler passes

glob ......................... argument expander

init ......................... initializer process

kbd .......................... map of TTY 37 keyboard

liba ......................... standard assembly-language library

libb ......................... standard B library

libf ......................... standard Fortran library

login, logout ................ logging on and logging off the system

msh .......................... mini Shell

suftab ....................... roff's suffix table

tabs ......................... set tab stops on typewriter



































                              INDEX





           as2(VII): assembler's pass   2

                 kbd(VII): map of TTY   37 keyboard

                     chmod(I): change   access mode of files

                            sdate(I):   adjust date and time

                mail(I): send mail to   another user

                   write(I): write to   another user

                                        a.out(V): assembler and loader output

                               ar(I):   archive (combine) files

                          archive(V):   archive file

                                        archive(V): archive file

                           glob(VII):   argument expander

                                        ar(I): archive (combine) files

                                        as2(VII): assembler's pass 2

                    dpt(VI): read DEC   ASCII paper tapes

                      bcd(I): convert   ASCII to BCD

                   atof(III): convert   ASCII to floating

                   atoi(III): convert   ASCII to integer

                   ascii(VII): map of   ASCII

          ctime(III): convert time to   ASCII

       ftoa(III): convert floating to   ASCII

        itoa(III): convert integer to   ASCII

                                        ascii(VII): map of ASCII

                                        as(I): assembler

                            a.out(V):   assembler and loader output

                               as(I):   assembler

                           ba(VII): B   assembler

                            as2(VII):   assembler's pass 2

                  liba(VII): standard   assembly-language library

                                        atof(III): convert ASCII to floating

                                        atoi(III): convert ASCII to integer

                             ba(VII):   B assembler

                             bc(VII):   B compiler

                          bilib(VII):   B interpreter library

                  libb(VII): standard   B library

                        b(I): compile   B program

                      brt1,brt2(VII):   B start and finish

                  log(III): logarithm   base e

                                        bas(I): BASIC dialect

                              bas(I):   BASIC dialect

              basic(VI): DEC supplied   BASIC

                                        basic(VI): DEC supplied BASIC

                                        ba(VII): B assembler

             bcd(I): convert ASCII to   BCD

                                        bcd(I): convert ASCII to BCD

                                        bc(VII): B compiler

                               su(I):   become super-user

                                        b(I): compile B program

                                        bilib(VII): B interpreter library

                             bppt(V):   binary paper tape format

                      dbppt(I): write   binary paper tape

                       lbppt(I): read   binary paper tape

                    dli(VI): load DEC   binary paper tapes

 strip(I): remove symbols, relocation   bits

                                        bj(VI): the game of blackjack

                  bj(VI): the game of   blackjack

                          bproc(VII):   boot procedure

                                        boot(I): reboot system

                                        bppt(V): binary paper tape format

                                        bproc(VII): boot procedure

               break(II): set program   break

                                        break(II): set program break

                                        brt1,brt2(VII): B start and finish

                          dc(I): desk   calculator

                       cal(VI): print   calender

                                        cal(VI): print calender

                            cemt(II):   catch EMT traps

                          ilgins(II):   catch illegal instruction trap

                            intr(II):   catch or inhibit interrupts

                            quit(II):   catch or inhibit quits

                                        cat(I): concatenate (or print) files

                                        cemt(II): catch EMT traps

                            chmod(I):   change access mode of files

                           chmod(II):   change mode of file

                           chown(II):   change owner of file

                            chown(I):   change owner of files

                            chdir(I):   change working directory

                           chdir(II):   change working directory

                     putc(III): write   character or word

                        get(III): get   character

                                        chdir(I): change working directory

                                        chdir(II): change working directory

                            check(I):   check consistency of file system

                                        check(I): check consistency of file system

               chess(VI): the game of   chess

                                        chess(VI): the game of chess

                                        chmod(I): change access mode of files

                                        chmod(II): change mode of file

                                        chown(I): change owner of files

                                        chown(II): change owner of file

                           close(II):   close open file

                                        close(II): close open file

                                        cmp(I): compare file contents

                       ar(I): archive   (combine) files

                               sh(I):   command interpreter

                              cmp(I):   compare file contents

                                b(I):   compile B program

                              for(I):   compile Fortran program

            f1,f2,f3,f4(VII): Fortran   compiler passes

                           bc(VII): B   compiler

                              cat(I):   concatenate (or print) files

                      check(I): check   consistency of file system

                             tty(IV):   console typewriter

                          ls(I): list   contents of directory

                 cmp(I): compare file   contents

                              bcd(I):   convert ASCII to BCD

                           atof(III):   convert ASCII to floating

                           atoi(III):   convert ASCII to integer

                           ftoa(III):   convert floating to ASCII

                           itoa(III):   convert integer to ASCII

                          ctime(III):   convert time to ASCII

                               cp(I):   copy file

                             core(V):   core image file

                             mem(IV):   core memory as file

                                        core(V): core image file

                      sin(III): sine,   cosine

            wc(I): get (English) word   count

                                        cp(I): copy file

                            mkdir(I):   create directory

                           mkdir(II):   create directory

                           creat(II):   create file

                            fork(II):   create new process

                                        creat(II): create file

                                        ctime(III): convert time to ASCII

                                        das(VI): disassembler

                         date(I): get   date and time of day

                     sdate(I): adjust   date and time

                      smdate(II): set   date modified of file

                                        date(I): get date and time of day

        date(I): get date and time of   day

                                        db(I): symbolic debugger

                                        dbppt(I): write binary paper tape

                                        dc(I): desk calculator

                      db(I): symbolic   debugger

                        dpt(VI): read   DEC ASCII paper tapes

                        dli(VI): load   DEC binary paper tapes

                           basic(VI):   DEC supplied BASIC

                   tap0,...,tap7(IV):   DECtape file

                       dtf(I): format   DECtape

                       rew(I): rewind   DECtape

                   tap(I): manipulate   DECtape

                     rmdir(I): remove   (delete) directory

                        rm(I): remove   (delete) file

                              dsw(I):   delete files interactively

                   unlink(II): remove   (delete) file

                   mesg(I): permit or   deny messages

                switch(III): transfer   depending on value

                               dc(I):   desk calculator

                                        df(I): find free disk space

                        bas(I): BASIC   dialect

                        directory(V):   directory format

             chdir(I): change working   directory

            chdir(II): change working   directory

              ls(I): list contents of   directory

                     mkdir(I): create   directory

                    mkdir(II): create   directory

            rmdir(I): remove (delete)   directory

                                        directory(V): directory format

                             das(VI):   disassembler

                          rf0(IV): RF   disk file

                          rk0(IV): RK   disk file

                         rkl(I): load   disk from tape

                     df(I): find free   disk space

                         rkd(I): dump   disk to tape

                          du(I): find   disk usage

                    rkf(I): format RK   disk

                          umount(II):   dismount file system

                           umount(I):   dismount removable file system

                                        dli(VI): load DEC binary paper tapes

                                        dpt(VI): read DEC ASCII paper tapes

                                        dsw(I): delete files interactively

                                        dtf(I): format DECtape

                                        du(I): find disk usage

                              rkd(I):   dump disk to tape

                         od(I): octal   dump of file

                                        ed(I): text editor

                          ld(I): link   editor (loader)

                          ed(I): text   editor

             log(III): logarithm base   e

                      cemt(II): catch   EMT traps

                           wc(I): get   (English) word count

                                        exec(II): execute program file

                            exec(II):   execute program file

                  exit(II): terminate   execution

                                        exit(II): terminate execution

                  glob(VII): argument   expander

                                        exp(III): exponential function

                            exp(III):   exponential function

                                        f1,f2,f3,f4(VII): Fortran compiler passes

                      cmp(I): compare   file contents

                       type(I): print   file page-by-page

                         stat(I): get   file status

                        stat(II): get   file status

                      file system(V):   file system format

       check(I): check consistency of   file system

                  mkfs(I): initialize   file system

            mount(I): mount removable   file system

                     mount(II): mount   file system

        umount(I): dismount removable   file system

                 umount(II): dismount   file system

                                        file system(V): file system format

                        find(I): find   file with given name

                         pr(I): print   file with headings

                  archive(V): archive   file

            chmod(II): change mode of   file

           chown(II): change owner of   file

                close(II): close open   file

                  core(V): core image   file

                          cp(I): copy   file

                    creat(II): create   file

            exec(II): execute program   file

            fstat(II): status of open   file

                    link(II): link to   file

                       ln(I): link to   file

              mem(IV): core memory as   file

                mv(I): move or rename   file

                 od(I): octal dump of   file

                       open(II): open   file

                  passwd(V): password   file

                       read(II): read   file

                     rf0(IV): RF disk   file

                     rk0(IV): RK disk   file

               rm(I): remove (delete)   file

                       dsw(I): delete   files interactively

             ar(I): archive (combine)   files

       cat(I): concatenate (or print)   files

      chmod(I): change access mode of   files

            chown(I): change owner of   files

     smdate(II): set date modified of   file

                     sort(VI): sort a   file

                          sum(I): sum   file

           tap0,...,tap7(IV): DECtape   file

          unlink(II): remove (delete)   file

                     write(II): write   file

                               du(I):   find disk usage

                             find(I):   find file with given name

                               df(I):   find free disk space

                              tty(I):   find name of terminal

                            tell(II):   find read or write pointer

                               un(I):   find undefined symbols

                                        find(I): find file with given name

          brt1,brt2(VII): B start and   finish

                   ftoa(III): convert   floating to ASCII

          atof(III): convert ASCII to   floating

                         fptrap(III):   floating-point simulator

                                        for(I): compile Fortran program

                                        fork(II): create new process

                    form(I): generate   form letter

                              dtf(I):   format DECtape

                              rkf(I):   format RK disk

                             roff(I):   format text for printing

           bppt(V): binary paper tape   format

              directory(V): directory   format

          file system(V): file system   format

                                        form(I): generate form letter

                    f1,f2,f3,f4(VII):   Fortran compiler passes

                  libf(VII): standard   Fortran library

                      for(I): compile   Fortran program

                                        fptrap(III): floating-point simulator

                          df(I): find   free disk space

                    rkl(I): load disk   from tape

                                        fstat(II): status of open file

                                        ftoa(III): convert floating to ASCII

                exp(III): exponential   function

                          bj(VI): the   game of blackjack

                       chess(VI): the   game of chess

                         moo(VI): the   game of MOO

                         ttt(VI): the   game of tic-tac-toe

                             form(I):   generate form letter

                            get(III):   get character

                             date(I):   get date and time of day

                               wc(I):   get (English) word count

                             stat(I):   get file status

                            stat(II):   get file status

                               tm(I):   get time information

                            time(II):   get time of year

                            gtty(II):   get typewriter mode

                          getuid(II):   get user ID

                                        get(III): get character

                                        getuid(II): get user ID

              find(I): find file with   given name

                                        glob(VII): argument expander

                                        gtty(II): get typewriter mode

                              hup(I):   hang up typewriter

               pr(I): print file with   headings

                                        hup(I): hang up typewriter

                 getuid(II): get user   ID

                 setuid(II): set user   ID

           uids(V): map names to user   ID's

                                        ilgins(II): catch illegal instruction trap

                    ilgins(II): catch   illegal instruction trap

                        core(V): core   image file

                      tm(I): get time   information

              utmp(V): logged-in user   information

                   intr(II): catch or   inhibit interrupts

                   quit(II): catch or   inhibit quits

                             mkfs(I):   initialize file system

                           init(VII):   initializer process

                                        init(VII): initializer process

            ilgins(II): catch illegal   instruction trap

                   itoa(III): convert   integer to ASCII

          atoi(III): convert ASCII to   integer

                 dsw(I): delete files   interactively

                        bilib(VII): B   interpreter library

                       sh(I): command   interpreter

           intr(II): catch or inhibit   interrupts

                                        intr(II): catch or inhibit interrupts

                                        itoa(III): convert integer to ASCII

                                        kbd(VII): map of TTY 37 keyboard

              kbd(VII): map of TTY 37   keyboard

                                        lbppt(I): read binary paper tape

                                        ld(I): link editor (loader)

               form(I): generate form   letter

                                        liba(VII): standard assembly-language library

                                        libb(VII): standard B library

                                        libf(VII): standard Fortran library

            bilib(VII): B interpreter   library

liba(VII): standard assembly-language   library

                libb(VII): standard B   library

          libf(VII): standard Fortran   library

                               ld(I):   link editor (loader)

                            link(II):   link to file

                               ln(I):   link to file

                                        link(II): link to file

                               ls(I):   list contents of directory

                                        ln(I): link to file

                             dli(VI):   load DEC binary paper tapes

                              rkl(I):   load disk from tape

              a.out(V): assembler and   loader output

                   ld(I): link editor   (loader)

                            log(III):   logarithm base e

                             utmp(V):   logged-in user information

                                        log(III): logarithm base e

                                        ls(I): list contents of directory

                        mail(I): send   mail to another user

                                        mail(I): send mail to another user

                              tap(I):   manipulate DECtape

                             uids(V):   map names to user ID's

                          ascii(VII):   map of ASCII

                            kbd(VII):   map of TTY 37 keyboard

                                        mem(IV): core memory as file

                        mem(IV): core   memory as file

                                        mesg(I): permit or deny messages

                                        mesg(III): print string on typewriter

              mesg(I): permit or deny   messages

                                        mkdir(I): create directory

                                        mkdir(II): create directory

                                        mkfs(I): initialize file system

                    chmod(II): change   mode of file

              chmod(I): change access   mode of files

                        stty(II): set   mode of typewriter

             gtty(II): get typewriter   mode

                 smdate(II): set date   modified of file

                 moo(VI): the game of   MOO

                                        moo(VI): the game of MOO

                           mount(II):   mount file system

                            mount(I):   mount removable file system

                                        mount(I): mount removable file system

                                        mount(II): mount file system

                               mv(I):   move or rename file

                            seek(II):   move read or write pointer

                                        mv(I): move or rename file

                         tty(I): find   name of terminal

        find(I): find file with given   name

                         nm(I): print   namelist

                         uids(V): map   names to user ID's

                     fork(II): create   new process

                                        nm(I): print namelist

                               od(I):   octal dump of file

                                        od(I): octal dump of file

                     close(II): close   open file

                 fstat(II): status of   open file

                            open(II):   open file

                                        open(II): open file

                  cat(I): concatenate   (or print) files

       a.out(V): assembler and loader   output

                    chown(II): change   owner of file

                     chown(I): change   owner of files

                  type(I): print file   page-by-page

                      bppt(V): binary   paper tape format

               dbppt(I): write binary   paper tape

                lbppt(I): read binary   paper tape

                     ppt(IV): punched   paper tape

             dli(VI): load DEC binary   paper tapes

              dpt(VI): read DEC ASCII   paper tapes

                as2(VII): assembler's   pass 2

   f1,f2,f3,f4(VII): Fortran compiler   passes

                                        passwd(V): password file

                           passwd(V):   password file

                             mesg(I):   permit or deny messages

         seek(II): move read or write   pointer

         tell(II): find read or write   pointer

                                        ppt(IV): punched paper tape

                                        pr(I): print file with headings

                             cal(VI):   print calender

                             type(I):   print file page-by-page

                               pr(I):   print file with headings

              cat(I): concatenate (or   print) files

                               nm(I):   print namelist

                           mesg(III):   print string on typewriter

                          ptime(III):   print time

             roff(I): format text for   printing

                     bproc(VII): boot   procedure

                 fork(II): create new   process

               init(VII): initializer   process

                    rele(II): release   processor

                   wait(II): wait for   process

                       break(II): set   program break

                    exec(II): execute   program file

                      b(I): compile B   program

              for(I): compile Fortran   program

                                        ptime(III): print time

                             ppt(IV):   punched paper tape

                                        putc(III): write character or word

                                        quit(II): catch or inhibit quits

           quit(II): catch or inhibit   quits

                            lbppt(I):   read binary paper tape

                             dpt(VI):   read DEC ASCII paper tapes

                            read(II):   read file

                       seek(II): move   read or write pointer

                       tell(II): find   read or write pointer

                                        read(II): read file

                             boot(I):   reboot system

                            rele(II):   release processor

                                        rele(II): release processor

            strip(I): remove symbols,   relocation bits

                   tty0,...,tty5(IV):   remote typewriter

                      mount(I): mount   removable file system

                  umount(I): dismount   removable file system

                            rmdir(I):   remove (delete) directory

                               rm(I):   remove (delete) file

                          unlink(II):   remove (delete) file

                            strip(I):   remove symbols, relocation bits

                       mv(I): move or   rename file

                                        rew(I): rewind DECtape

                              rew(I):   rewind DECtape

                             rf0(IV):   RF disk file

                                        rf0(IV): RF disk file

                             rk0(IV):   RK disk file

                       rkf(I): format   RK disk

                                        rk0(IV): RK disk file

                                        rkd(I): dump disk to tape

                                        rkf(I): format RK disk

                                        rkl(I): load disk from tape

                                        rmdir(I): remove (delete) directory

                                        rm(I): remove (delete) file

                                        roff(I): format text for printing

                                        sdate(I): adjust date and time

                                        seek(II): move read or write pointer

                             mail(I):   send mail to another user

                          smdate(II):   set date modified of file

                            stty(II):   set mode of typewriter

                           break(II):   set program break

                           stime(II):   set system time

                          setuid(II):   set user ID

                                        setuid(II): set user ID

                                        sh(I): command interpreter

          fptrap(III): floating-point   simulator

                            sin(III):   sine, cosine

                                        sin(III): sine, cosine

                                        smdate(II): set date modified of file

                            sort(VI):   sort a file

                                        sort(VI): sort a file

                df(I): find free disk   space

                           liba(VII):   standard assembly-language library

                           libb(VII):   standard B library

                           libf(VII):   standard Fortran library

                    brt1,brt2(VII): B   start and finish

                                        stat(I): get file status

                                        stat(II): get file status

                           fstat(II):   status of open file

                    stat(I): get file   status

                   stat(II): get file   status

                                        stime(II): set system time

                     mesg(III): print   string on typewriter

                                        strip(I): remove symbols, relocation bits

                                        stty(II): set mode of typewriter

                                        su(I): become super-user

                              sum(I):   sum file

                                        sum(I): sum file

                        su(I): become   super-user

                       basic(VI): DEC   supplied BASIC

                                        switch(III): transfer depending on value

                               db(I):   symbolic debugger

                     strip(I): remove   symbols, relocation bits

                un(I): find undefined   symbols

                 file system(V): file   system format

                       stime(II): set   system time

                      boot(I): reboot   system

  check(I): check consistency of file   system

             mkfs(I): initialize file   system

       mount(I): mount removable file   system

                mount(II): mount file   system

   umount(I): dismount removable file   system

            umount(II): dismount file   system

                                 file   system(V): file system format

                who(I): who is on the   system

                                        tap0,...,tap7(IV): DECtape file

                bppt(V): binary paper   tape format

         dbppt(I): write binary paper   tape

          lbppt(I): read binary paper   tape

               ppt(IV): punched paper   tape

                 rkd(I): dump disk to   tape

               rkl(I): load disk from   tape

       dli(VI): load DEC binary paper   tapes

        dpt(VI): read DEC ASCII paper   tapes

                                        tap(I): manipulate DECtape

                                        tell(II): find read or write pointer

                 tty(I): find name of   terminal

                            exit(II):   terminate execution

                               ed(I):   text editor

                      roff(I): format   text for printing

                 ttt(VI): the game of   tic-tac-toe

                           tm(I): get   time information

                date(I): get date and   time of day

                        time(II): get   time of year

                  ctime(III): convert   time to ASCII

                                        time(II): get time of year

                    ptime(III): print   time

            sdate(I): adjust date and   time

                stime(II): set system   time

                                        tm(I): get time information

                         switch(III):   transfer depending on value

ilgins(II): catch illegal instruction   trap

                  cemt(II): catch EMT   traps

                                        ttt(VI): the game of tic-tac-toe

                     kbd(VII): map of   TTY 37 keyboard

                                        tty0,...,tty5(IV): remote typewriter

                                        tty(I): find name of terminal

                                        tty(IV): console typewriter

                                        type(I): print file page-by-page

                        gtty(II): get   typewriter mode

                      hup(I): hang up   typewriter

           mesg(III): print string on   typewriter

                stty(II): set mode of   typewriter

            tty0,...,tty5(IV): remote   typewriter

                     tty(IV): console   typewriter

                                        uids(V): map names to user ID's

                                        umount(I): dismount removable file system

                                        umount(II): dismount file system

                          un(I): find   undefined symbols

                                        un(I): find undefined symbols

                                        unlink(II): remove (delete) file

                     du(I): find disk   usage

                      getuid(II): get   user ID

                      setuid(II): set   user ID

                uids(V): map names to   user ID's

                   utmp(V): logged-in   user information

        mail(I): send mail to another   user

           write(I): write to another   user

                                        utmp(V): logged-in user information

   switch(III): transfer depending on   value

                            wait(II):   wait for process

                                        wait(II): wait for process

                                        wc(I): get (English) word count

                              who(I):   who is on the system

                                        who(I): who is on the system

                   find(I): find file   with given name

                    pr(I): print file   with headings

                 wc(I): get (English)   word count

        putc(III): write character or   word

                     chdir(I): change   working directory

                    chdir(II): change   working directory

                            dbppt(I):   write binary paper tape

                           putc(III):   write character or word

                           write(II):   write file

               seek(II): move read or   write pointer

               tell(II): find read or   write pointer

                            write(I):   write to another user

                                        write(I): write to another user

                                        write(II): write file

                time(II): get time of   year