199 lines
9.8 KiB
Plaintext
199 lines
9.8 KiB
Plaintext
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===============================================================================
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rush2112
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pRESENTS
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a hale pRODUCTION
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h ACKERS a GAINST l AW e NFORCEMENT
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cALL hale hQ. (619)660-67XX
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aCTIVE hale MEMBERS ARE: rIPPER, tRASHMAN, rUSH2112.
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tHE uNDERGROUND nEWSLETTER: vOL i. iSSUE i, pART i
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===============================================================================
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nOTE: fEEL FREE TO DISTRIBUTE THE FILE PROVIDED NONE OF ITS CONTENTS OR
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CREDITS ARE CHANGED.
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tOPIC: a gUIDE TO uNIX sYSTEMS, pART i.
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dATE: sEPTEMBER 1, 1989.
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fOREWORD: tHIS FILE IS COMPILED FROM MY EXPERIENCES ON BOTH bsd AND sYS v
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uNIX ON vax 750/780 MAINFRAMES, at&t 3b20 AND pYRAMID tECHNOLOGY'S
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MAINFRAMES.
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iN TODAY'S WORLD, AS A HACKER, YOU ARE NOTHING UNLESS YOU LEARN SOME
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OF THE MORE POPULAR OPERATING SYSTEMS AROUND USED ON MINIS, MAINFRAMES, SUPER-
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COMPUTERS AND THE LIKE. iN THIS FILE i WILL ATTEMPT (TO THE BEST OF MY
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ABILITY) TO INTRODUCE YOU TO ONE OF THOSE OPERATING SYSTEMS - NAMELY - THE
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WORLD OF uNIX. iT IS HOPED THAT BY READING THIS FILE YOU CAN PICK UP PERHAPS
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ENOUGH OF A WORKING KNOWLEDGE SO THAT IF BY CHANCE IN YOUR HACKING EXPLOITS YOU
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COME ACROSS A uNIX SYSTEM (AND YOU WILL) YOU'LL KNOW WHAT TO DO.
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tHERE IS no way TO COVER EVERYTHING ABOUT uNIX IN A FILE SO THIS WILL
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BE THE FIRST OF MANY THAT i HOPE TO RELEASE IN THE FUTURE. iF i FIND THERE ARE
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STUFF i HAVE NOT MENTIONED i WILL WRITE MORE FILES AS NEEDED. iN pART ii, i
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PLAN TO GIVE YOU A TUTORIAL ON WHAT TO DO WHILE YOU'RE ON-LINE IN REGARDS TO
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HACKING AND USING ESSENTIAL SYSTEM UTILITIES. hAVE FUN.
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uSUALLY (UNLESS MODIFIFIED BY THE SYSTEM ADMINISTRATOR OR ONE WITH SUCH
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PRIVILEGES), YOU CAN TELL IF YOU'VE CONNECTED TO A uNIX SYSTEM OF SOME TYPE BY
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THE LOGIN PROMPT WHICH LOOKS LIKE THIS:
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LOGIN:
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pRETTY SIMPLE HUH? aNYWAY, THAT IS THE STANDARD LOGIN PROMPT, IT MAY OR MAY
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NOT BE PRECEDED BY A MESSAGE TELLING YOU WHAT TYPE OF uNIX OR SYSTEM YOU HAVE
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CONNECTED TO.
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iF YOU TRY TO LOGIN WITH AN ILLEGAL LOGIN NAME AND/OR AN ILLEGAL
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PASSWORD THE SYSTEM WILL RESPOND AS SUCH AND AS YOU TO TRY AGAIN:
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LOGIN:HACKER
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PASSWORD:
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LOGIN INCORRECT
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LOGIN:
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(nOTE THE PASSWORD IS NOT ECHOED IN ANY FORM)
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iN pART i OF THIS uNIX TUTORIAL i'D LIKE TO START WITH AN OVERVIEW OF
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THE uNIX SYSTEM BEFORE i GET INTO SOME OF THE MORE INTERESTING STUFF (SO BEAR
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WITH ME ALL YOU uNIX EXPERTS). tHEN i WILL GO THROUGH THE LOGIN PROCESS AND
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THE /ETC/PASSWD FILE AND HOW IT IS STRUCTURED. tHIS WILL NOT BE AN IN-DEPTH
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LOOK AT ALL, MERELY AN OVERVIEW. sOME DAY i WILL WRITE AN IN-DEPTH STUDY TO
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ACCOMPANY THIS FILE AND THE FILES THAT FOLLOW FOR THE MORE ADVANCE USER/HACKER.
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tHERE ARE BASICALLY 2 TYPES OF uNIX SYSTEMS THAT YOU WILL MOST LIKELY
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COME ACROSS. tHEY ARE:
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i. bsd uNIX - FROM uc bERKELEY'S (b)ERKELEY (s)OFTWARE (d)ISTRIBUTORS
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ii. sYSTEM v unix - FROM at&t (HOW NICE - i KNOW ALL YOU PHREAKERS ARE SMILING!)
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(oTHER SPINOFF'S OF THE ABOVE 2 WILL NOT BE DISCUSSED - SUCH AS uLTRIX,
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mINIX, xENIX, ETC...)
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tHEY ARE ALIKE IN MANY RESPECTS BUT BOTH HAVE THEIR DIFFERENCES, HENCE
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THEIR ARE ADVANTAGES AND DISADVANTAGES TO BOTH OF THE SYSTEMS, bsd AND sYS v.
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pERHAPS THE MAIN DIFFERENCE BETWEEN THE TWO ARE THE DEFAULT SHELL THAT EACH
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USES AS THE USER INTERFACE TO THE SYSTEM UTILITIES.
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bsd uNIX DEFAULTS TO THE CSH (c-sHELL) WHILE at&t'S sYS v USES THE SH
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(bOURNE SHELL). bUT ON BOTH OF THESE SYSTEMS BOTH SHELL TYPES ARE AVAILABLE TO
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THE USER. a THIRD OPTIONAL SHELL WHICH IS ALSO PRETTY POPULAR IS THE KSH
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(kORN SHELL). tHE WAY TO RECOGNIZE THE DEFAULT SHELLS WHEN YOU SEE THEM IS BY
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THEIR DEFAULT PROMPT. tHE CSH USES THE % SYMBOL AS THE PROMPT WHILE THE SH
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USES THE $ SYMBOL AS THE PROMPT.
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nOW LET'S TALK ABOUT FILES, SHALL WE? tHE most IMPORTANT FILE OF ALL
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ON any unix SYSTEM IS THE PASSWORD FILE. tHIS FILE HOLDS INFORMATION ABOUT
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ALL THE ACCOUNTS ON THE SYSTEM, PASSWORDS, AND OTHER INFORMATION. wITHOUT
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THIS FILE NO ONE CAN LOG IN AND USE THE SYSTEM. yOU CAN FIND THIS FILE ON ANY
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SYSTEM IN THE /ETC DIRECTORY. iT IS CALLED SIMPLY 'PASSWD'. tHE FULL
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PATHNAME IS /ETC/PASSWD (OF COURSE).
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tHE /ETC/PASSWD FILE IS STUCTURED AS SUCH:
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eACH USER HAS AN ENTRY IN THE PASSWD FILE THAT HOLDS HIS ACCOUNT INFORMATION.
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aMONG THE INFORMATION INCLUDED ON EACH USER ENTRY LINE IS HIS LOGIN NAME,
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HIS PASSWORD (ENCRYPTED), HIS USER ID, HIS GROUP ID, HIS HOME DIRECTORY, HIS
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NAME, AND HIS STARTUP PROGRAM IF ANY. bASICALLY IT LOOKS SOMETHING LIKE THIS:
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------------------------ sAMPLE /ETC/PASSWD FILE --------------------------
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gENERAL FORMAT OF EACH ENTRY:
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LOGIN:PASSWORD:USER-id:GROUP-id:INFO:HOME DIRECTORY:STARTUP PROGRAM
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ROOT:aRLLZ76dNQ:0:0:tHE & OF aLL eVIL:/:/BIN/CSH
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JSMITH:yI83AMQ9:102:100:jOHN sMITH:/USR/JSMITH:/BIN/SH
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WHO::99:500:wHO'S ON:/USR/UCB:/BIN/WHO
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DAEMON:R6eEU:1:1:tHE devil HIMSELF:/ETC:/BIN/CSH
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BIN:MB033YT:3:3:tHE kEEPER OF THE fLAME:/ETC:/BIN/CSH
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INFO::508:501:lIBRARY USER GROUP:/USR2/INFO:/USR2/BIN/RSH
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.....
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..... [ AND SO ON ]
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.....
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----------------------------------------------------------------------------
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nOW WE'LL EXAMINE EACH ENTRY. rEMEMBER THAT EACH FIELD IS SEPARATED
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BY THE COLON. sO IN THE FIRST ENTRY IN /ETC/PASSWD GIVEN ABOVE, WE CAN TELL
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THE FOLLOWING ABOUT THE ENTRY.
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LOGIN NAME IS: ROOT
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pASSWORD (ENCRYPTED): aRLLZ76dNQ
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uSER id: 0
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gROUP id: 1
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iNFO (USUALLY OWNER): ROOT
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hOME dIRECTORY: /
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sTARTUP pROGRAM: /BIN/SH
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tHE SECOND ENTRY IN /ETC/PASSWD LOOKS LIKE THIS:
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LOGIN NAME IS: JSMITH
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pASSWORD (ENCRYPTED): yI83AMQ9
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uSER id: 102
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gROUP id: 100
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iNFO (USUALLY OWNER): jOHN sMITH
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hOME dIRECTORY: /USR/JSMITH
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sTARTUP pROGRAM: /BIN/SH
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bUT NOW YOU GET THE GENERAL FORMAT...SO LET'S DISCUSS SOME THINGS
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ABOUT THE FIELD.
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i. tHE LOGIN FIELD
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tHIS IS THE LOGIN NAME THAT YOU USE TO LOGIN AT THE PROMPT OF THE uNIX
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SYSTEM. dURING THE LOGIN PROCESS, AFTER YOU ENTER THE LOGIN AND THE PASSWORD
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THE SYSTEM WILL THEN CALL ROUTINES TO SEARCH THE 1ST FIELD OF EACH ENTRY
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IN /ETC/PASSWD TO SEE IF ANY LOGIN NAMES MATCH UP WITH THE ONE YOU HAVE GIVEN
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IT. iF NONE EXISTS IT WILL REPORT THE "LOGIN INCORRECT" MESSAGE AND START
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PROMPTING FOR A NEW LOGIN NAME AND NEW PASSWORD.
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ii. tHE pASSWORD FIELD
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iF THE LOGIN NAME IS VALID, uNIX THEN TAKES YOUR PASSWORD ENTRY AND ENCRYPTS
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IT THEN COMPARES IT AGAINST THE ENCRYPTED PASSWORD IN THE 2ND FIELD OF THE
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LOGIN NAME ENTRY (SEE i. tHE LOGIN FIELD). iF THE TWO PASSWORDS MATCH UP, THE
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LOGIN PROCESS WILL CONTINUE, OTHERWISE THE "LOGIN INCORRECT" MESSAGE WILL BE
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DISPLAYED. i'LL EXPLAIN LATER WHAT GOES ON WHEN COMPARISONS OF THE ENCRYPTED
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PASSWORDS TAKE PLACE. iF THE pASSWORD fIELD CONTAINS NULL :: THEN NO PASSWORD
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IS NEEDED AND THE SYSTEM LOGS YOU INTO THE HOME DIRECTORY AND EXECUTES THE
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STARTUP PROGRAM. iF THE pASSWORD fIELD CONTAINS :,.: THEN UPON LOGIN THE
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SYSTEM WILL RUN THE PASSWD UTILITY AND ASSIGN THAT ACCOUNT A PASSWORD. (tHIS
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IS NICE IF YOU'RE A SYSTEM ADMINISTRATOR, YOU CREATE AN ACCOUNT FOR YOUR
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FRIEND THEN PUT THE ",." IN THE PASSWORD FIELD AND HE'LL SET HIS OWN PASSWORD
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UPON LOGIN.
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iii. tHE uid (uSERid) FIELD
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iF EVERYTHING IS CORRECT (LOGIN NAME AND PASSWORD) THEN THE SYSTEM PROCEEDS
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TO PUT YOUR IN YOUR HOME DIRECTORY. yOU ARE THEN GIVEN A uid FROM YOUR ENTRY
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IN THE /ETC/PASSWD FILE. aLL uid'S FALL IN THE RANGE 0-65535 WITH 0 AS THE
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SUPERUSER uid (SEE /ETC/PASSWD EXAMPLE). tHE SYSTEM RESERVES uid 0-99 FOR
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SPECIAL ACCOUNTS. uid'S ARE USED BY THE SYSTEM AND ITS UTILITIES TO CONTROL
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BOTH ACCESS LEVELS AND FILE OWNERSHIP (AS DETERMINED BY THE LS UTILITY - MORE
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ON THAT LATER).
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iv. tHE gid (gROUPid) FIELD
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tHE gROUP id IS USED TO ASSOCIATE THE USER WITH A CERTAIN GROUP, USED BY
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uNIX PRIMARILY FOR ACCESS LEVELS AS DETERMINED BY FILE PROTECTIONS. (I.E.
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A MEMBER WHO IS NOT IN A GROUP CAN NOT GET GROUP PRIVILEGES ON FILES FOR THAT
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GROUP, EVEN THOUGH FILE PROTECTIONS FOR THE FILE SAY ALL PRIVILEGES TO GROUP
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USERS.) gid'S FALL IN THE RANGE 0-655535 WITH gid 1 BEING THE DEFAULT. aLL
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gid'S BETWEEN 0-99 ARE RESERVED.
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v. tHE iNFORMATION FIELD
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tHIS FIELD USUALLY HOLDS THE ACCOUNT OWNER'S NAME THOUGH IT CAN BE USED
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FOR ANYTHING ACTUALLY. i HAVE SEEN IT USED TO DESCRIBE THE ACCOUNT FUNCTION
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(SEE THE SAMPLE /ETC/PASSWD FILE ON THE ENTRY FOR LOGIN NAME "WHO"), AND ALSO
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TO HOLD PEOPLE'S PHONE EXTENSION, ETC..
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vi. tHE hOME dIRECTORY fIELD
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tHIS FIELD SHOULD HAVE THE FULL PATHNAME TO YOUR HOME DIRECTORY. oN MANY
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unix SYSTEMS IT IS USUALLY IN THE FORMAT OF /USR/*LOGINNAME! (sEE THE
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ENTRY FOR LOGIN NAME "JSMITH"). nOT NECESSARILY YOUR permanent HOME
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DIRECTORY, ONE CAN CHANGE IT BY REASSIGNING AN ALTERNATE PATH TO THE SYSTEM
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VARIABLE $home (ON sYS v).
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vii. tHE pROGRAM fIELD
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uSUALLY THIS FIELD HOLDS THE STARTUP PROGRAM TO EXECUTE ONCE THE LOGIN
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PROCEDURE HAS BEEN COMPLETED. iF LEFT BLANK THEN THE DEFAULT STARTUP PROGRAM
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WILL BE THE SHELL ASSIGNED TO THE uNIX SYSTEM. iN THE OUR EXAMPLE /ETC/PASSWD
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FILE, THE ENTRY FOR LOGIN NAME WHO, WILL EXECUTE THE WHO COMMAND IN /BIN/WHO
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ONCE YOU LOG IN. hOWEVER, AFTER THE COMMAND FINISHES EXECUTING, IT WILL EXIT
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THE SYSTEM AS THERE IS NO PASSWORD ON THE ACCOUNT, THERE IS NO WAY TO STAY
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LOGGED IN. oN THE INFO ACCOUNT HOWEVER, YOU WILL REMAIN LOGIN UNTIL YOU TYPE
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EXIT OR LOGOUT OR ctrl-d AS THE PROGRAM RUNNING THERE IS A SHELL. tHOUGH NOT
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A FULL bOURNE SHELL OR c-SHELL, THE RESTRICTED SHELL (RSH) DOES ALLOW TO YOU
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PLAY AROUND A LITTLE.
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wELL, THAT ABOUT DOES IT FOR WHAT i WANT TO COVER IN pART i. lOOK FOR
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pART ii COMING OUT REAL SOON. i WILL BE GOING INTO DETAILS WHAT TO DO ONCE
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ONLINE WITH AN ACCOUNT AND HOW TO GO ABOUT GETTING AN ACCOUNT. tHIS FILE IS
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FOR INFORMATIONAL PURPOSES ONLY.
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------------------------------------------------------------------------------
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bROUGHT TO YOU BY: tHE aPPLE bANDIT 10-89
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Text-Files 2: |