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[Pages:16]Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

B?I 2. NGI D?NG ? PH?N QUYN V? QUN L? FILE

LU ?: TT C SINH VI?N THC HIN TR?N FILE IMAGE CA H IU H?NH CENTOS 7 ? C?I T C?C BUI THC H?NH TRC TI TH MC ? TO TI SINHVIEN

PHN 1: M FILE IMAGE CA H IU H?NH CENTOS 7 Bc 1: Khi ng phn mm m?y o VMware

- Sau khi khi ng VMware nh h?nh sau

Bc 2: M file image ca h iu h?nh CentOS 7 ? c?i

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

Tr?n m?n h?nh ch?nh VMware chn File ->Open... Chn n file image VMX ca CentOS 7

Bc 3: Khi ng v?o m?y o CentOS 7 Chut phi v?o m?y o chn Power -> Power On

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

PHN 2: NGI D?NG V? PH?N QUYN

NGI D?NG (USER)

Account tr?n Linux bao gm nhiu th?ng tin trong ? hai phn li?n quan n vic s dng l? username v? userID:

username: khi s dng login, g?n quyn, v.v.. ch?ng ta thc hin th?ng qua username, nhng h thng li hiu v? l?m theo userID.

userID: S i k?m vi username, h iu h?nh d?ng s n?y qun l?. Nh vy nu c? hai username kh?c nhau nhng d?ng chung mt userID, th? h thng xem hai t?n n?y ch l? mt.

- Quyn hn: Linux ch ph?n bit user l?m hai loi:

User c? quyn root: Tt c nhng user c? userID=0, thng th? vi mt m?y mi, ch?ng ta s c? ngay mt user t?n root v? c? userID=0. Nu ch?ng ta to ra mt user kh?c v? sau ? sa userID ca n? th?nh 0, th? l?c n?y n? c? quyn root y chang user t?n l? root ca h thng.

User thng: Tt c c?c user c? userID kh?c 0 iu l? ngi d?ng thng.

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

- User v? Group :Mi user tr?n linux bt buc phi thuc mt group n?o ? (gi l? Primary Group), ngo?i ra c?n c? th la chn tham gia v?o c?c group kh?c (gi l? Secondary Group), user c? th tham gia v?o ti a 16 Secondary Group. - Tr?n Linux, tt c th?ng tin v users v? groups iu c lu v?o c?c tp tin vn bn thng. V? vy thay v? bn d?ng lnh qun l? user, c? th m c?c files n?y ra sa trc tip. Tuy nhi?n ch l?m vy khi tht cn thit, v? vi mc ?ch hc tp m? th?i. Trc khi sa cha c?c bn n?n backup li.

Th?ng tin v c?c user c lu tr trong c?c files: /etc/passwd v? /etc/shadow. /etc/passwd: File n?y cha th?ng tin v user, iu khin vic login ca c?c user. File n?y c lu di dng ASCII, mi d?ng lu th?ng tin ca mt user, v? mi d?ng li ph?n th?nh c?c trng bng du hai chm. Nh vy th?ng tin ? c lu di dng mt "bng". Cu tr?c ca n? nh sau:

UserName : Password : UserID : PrincipleGroup : Comments : HomeDirectory : Shell ? ngha ca c th ca c?c trng:

1-usename: t?n ng nhp, ph?n bit Hoa/thng, n?n d?ng ch thng. 2-password: lu chui passwd ? hash, nu c? s dng /etc/shadow th? ?y s l?

ch x 3-user ID: h thng d?ng user ID ph?n bit ngi n?y vi ngi kh?c. 4-group ID: ?y l? Primary Group ca user n?y. 5-comment: m? t cho user. 6-Home Directory: Th mc home ca tng user, thng s nm trong

/home/tenuser 7-Shell: T?n chng tr?nh s thc thi ngay sau khi user login v?o. Nu kh?ng c?

shell user s kh?ng th login. Mc nhi?n tr?n Linux s d?ng bash shell ?y. Bn xem ni dung ca /etc/passwd bng lnh:

$ cat /etc/passwd

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

Sudo l? ch vit tt ca Superuser Do, dch n?m na l? "Si?u th?nh vi?n l?m [iu g? ?]". Ngha l? n? s cho ph?p mt th?nh vi?n c? th thc hin mt lnh n?o ? trong h thng di quyn ca mt th?nh vi?n kh?c (Superuser ?y ngha l? t?i khon root) m? h kh?ng cn cp quyn c bit.

kim tra hin ang User n?o: G? lnh whoami

H thng lu?n c? User root. C?ch chuyn t user thng sang User root: G? lnh su root

C?ch chuyn sang 1 user n?o ? g? lnh: su t?nuser

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

Th?m mi 1 user : to 1 user phi ng user root to

useradd t?n-user-cn-to V? d sau ?y to User thuchanh: G? lnh

useradd thuchanh Sau ? kim tra xem h thng ? to th?nh c?ng g? lnh: cat /etc/passwd | grep thuchanh

Sau khi user c to ra n? s kh?ng c? mt khu: th?m mt khu cho user thc hin lnh sau: passwd t?n-user-cn-thit-lp

Mc nh tr?n Linux, user t?n root s s hu mt th mc vi ng dn l? /root. C?c user mi th?m v?o s c? mt th mc ri?ng ti /home. V? d va to ra mt user t?n thuchanh th? s c? mt th mc t?n l? thuchanh trong /home. Kim tra th mc n?y bng lnh sau: ?y hin th 3 user ? c to nh b?n di

Xem th?ng tin cu h?nh mc nh khi to user mi c?ch m file: /etc/default/useradd

G? lnh: cat /etc/default/useradd

?y: - GROUP: l? ID ca group mc nh m? user s c a v?o khi to ra. - HOME: ng dn mc nh cha c?c th mc ca tng th?nh vi?n khi to ra.

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

- INACTIVE: Thi gian m? t?i khon s b kh?a vnh vin sau khi mt khu ca th?nh vi?n ? ht hn.

- EXPIRE: Ng?y m? t?i khon ca th?nh vi?n c to ra mc nh s b kh?a. Cu tr?c ng?y th?ng ?y l? YYYY-MM-DD (2016-05-02).

- SKEL: Th mc mu ca user m? khi to ra, user s t ng copy c?c file v? th mc trong ?y v?o th mc /home/t?n-user.

- SHELL: L? mt h v mc nh m? user s c s dng. Khi v?o SSH, g? c?c d?ng lnh Linux v?o v? thc thi, ? ch?nh l? ang d?ng Shell. Nu kh?ng mun user c to ra c? quyn s dng Shell th? trng phn n?y.

- CREATE_EMAIl_SPOOL: Cho th?nh vi?n c ph?p s dng mail tr?n server nu t?y chn l? yes. Mail s c lu trong file /var/mail/t?n-user hoc /var/spool/mail/t?n-user

PH?N QUYN USER

User root l? user c? quyn ti cao trong linux, thc hin nhiu lnh ch?ng ta cn quyn ca user root.

V? d: Sau ?y chuyn sang user thucthanh v? tin h?nh th?m mi 1 user t?n th2 nh sau

su ? thuchanh useradd th2 H thng s th?ng b?o kh?ng c? quyn

Qun l? Group

Mi user trong linux u thuc v 1 Group. C?c th?ng tin v group u cha trong file /etc/group hoc /etc/gshadows xem c?c group trong linux : Thc hin m file cha th?ng tin bng lnh cat /etc/group

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

Linux v? phn mm m? ngun m

GV Nguyn Vn ng ? Khoa CNTT ? H Thy li

Cu tr?c ca n? nh sau: GroupName : Password : GroupID : User1,User2,..., Usern

To 1 group mi : Thc hin lnh groupadd t?ngroup X?a 1 group: Thc hin lnh groupdel t?ngroup

Thc hin to user v? th?m v?o 1 group bng lnh sau: useradd -G t?n-group t?n-user

Thc hin th?m user ? tn ti ri v?o 1 group ? tn ti ri thc hin lnh sau: usermod -G t?n-group t?n-user

V? d sau th?m user thuchanh v?o group root Usermod ?G root thuchanh

Khi thc hin c?c lnh ?i hi quyn root n?y ?i hi phi chuyn sang user root mi thc hin c. Tuy nhi?n c? th thc hin c?c lnh ?i hi quyn root 1 user kh?c bng c?ch g? th?m "sudo" ngay trc lnh ?.

Tuy nhi?n kh?ng phi 1 user va c to ra ? c? th d?ng c lnh sudo. File /etc/sudoers. S cha th?ng tin v cu h?nh group n?o s c thc hin lnh sudo

G? lnh cat /etc/sudoers

Sau ? t?m n d?ng sau: D?ng n?y cha th?ng tin v group n?o s c chy tt c c?c lnh ti mi v tr?

B?i thc h?nh 2: Ngi d?ng ? ph?n quyn v? qun l? file

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