Command in Linux

Nguyn Vn Giang B mn MMT-VT

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*boot : kernel v cu hnh boot */bin : cc lnh c bn */dev : cc khai bo v thit b */etc : cu hnh h thng v ng dng */home : th mc ngi dng

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*/lib : th vin dng chung */mnt : th mc mount */proc : thng tin process */sbin : cc lnh qun tr */tmp : d liu tm */usr : ng dng v th vin */var : d liu tm v bin ng

**Ti a 255 k t, dng bt k k t no, k c cc k t c bit

*V d: Very ? long file + name . test

*Tp tin (th mc) n c bt u bng du chm .

*V d: .bash_history

**ng dn tuyt i: bt u bng / * V d : / /bin /usr /usr/bin

*ng dn tng i: khng bt u bng / * V d: etc/httpd/ usr/bin

*ng dn t bit * .. - th mc cha * . - th mc ang lm vic * ~ - th mc home ca ngi dng hin hnh

*V d: Nu ngi dng ang th mc /etc, mun tham chiu n tp tin /etc/vsftp.conf th ng dn tng i s l ./vsftp.conf

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** [root@localhost ~] _ * root: user ang log

* localhost: tn my

*~: th mc hin hnh

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**B thng dch dng lnh *ng dng c bit *Tng tc vi h iu hnh *Cung cp kh nng lp trnh n gin

*Ghi ch: C kh nhiu loi shell trn Linux, kim tra ang dng loi shell no:

*echo $SHELL

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**C php: command [flags] arg1 arg2 arg3 *Cc thnh phn cch nhau mt khong trng. *Cc c thng theo sau du - hoc -- (nht l cc

c nhiu k t)

* V d: ls -a -l -F * ls --color

*Nhiu c c th dng chung mt k t -, v d: ls -al tng ng ls -a -l

*Mt s lnh c bit, khng cn k t - trc cc c *Mun xem tr gip dng tham s --help hoc man. * V d: ls --help hoc man ls

**Tn tp tin hoc th mc lm tham s dng lnh c th dng khng tng minh.

*Dng k t thay th cho mt phn hoc ton b tn

** : mi chui k c rng *? : mt k t bt k * [] : tng ng vi mt trong cc k t * [!/^] : khng tng ng * \ : loi b ngha c bit ca cc k t *,?,)

**Nhn t ng in y dng lnh * username, hostname, command, filename * lit k tt c kh nng c th *V d: *$ cd /usr/lo (/usr/local) *$ cp *cp cpp cpio cproto *$ cd dir *dir1 dir2 dir3

*pwd

cd

ls

cp

mv

rm

find

more

grep

file

Xem th mc hin hnh Thay i th mc Lit k ni dung th mc Copy tp tin v th mc Chuyn hoc i tn file Xa tp tinh v th mc Tm kim Xem ni dung trn tng trang In cc dng ng vi tiu ch t ra Xc nh loi file.

**Cho bit ngi dng ang ti th mc no: pwd

*Chuyn th mc (change directory): cd

*V d: *cd /etc

*cd ~ ( ~: macro tng trng cho home directory ca ngi dng)

*cd /home/sv

*cd ..

*cd ../../data

**Xut 1 chui ra mn hnh *echo Hello World

*Xut chui , khng xung dng *echo n Nhap vao ten ban:

*Xut gi tr cc bin *Echo $HOME

**Lit k ni dung th mc: lnh LS

**-a: List all entries, including those beginning with a dot (hidden files, including ., ..)

*-A: Same as -a excluding . and .. *-d: If argument is a directory, then do not list

the contents of that directory

*-l: List in a long format *-F : Display file type ( /, *, @ ) *-R: Recursively list the contents of all subdirs.

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*Alias: t cc tn tt cho lnh

**mkdir to th mc *$mkdir p dir3/dir4

* (tham s -p: to th mc cha nu cha tn ti)

*rmdir xa th mc rng *touch to file rng *$ touch file.txt

**cp : copy file *$ cp file1 file2

*$ cp file1 dir1

*-f : ghi , -i : hi trc khi ghi *-R,-r : copy ton b th mc *$ cp r dir1 dir2

**mv di chuyn/ i tn *$ mv file1 file2 *$ mv dir1 dir2 * rm xa file/ th mc *$ rm file1 file2 *$ rm r dir3 *Tham s -r: xa c th mc v tp tin con * ln to lin kt (link), c th xem nh mt shortcut

trong windows

*$ ln s file1 file2

*** : mi chui k c rng *? : mt k t bt k *[] : tng ng vi mt trong cc k t *[!/^] : khng tng ng *\ : loi b ngha c bit

**Redirection: Chuyn hng dng d liu sang ni khc.

* nh hng: * < : nhp * > : xut, ghi * >> : xut, ghi tip theo (append)

*V d: * ls l / > /root/list.txt : lit k ni dung th mc / , kt qu

khng xut ra mn hnh m xut ra file /root/list.txt. Nu file tn ti s b ghi

* ls l / >> /root/list.txt: tng t nh trn, nhng thay v ghi (>) s ghi tip vo phn sau ca file (>>)

**Cc dng d liu chun: *stdin 0

*stdout 1

*stderr 2

*V d: Thc hin lnh ls, cc thng bo li s xut ra file error.txt

* ls R / 2>/root/error.txt

**Pipe: Kt qu output ca mt lnh trc -> d liu input ca lnh sau, s dng k t |

*V d: ls R / | less *cho php xem ni dung theo tng trang. *Duyt mn hnh vi less *Enter: dng k tip *Spacebar: trang k tip *b: trang trc *q: Thot

**Lnh TEE: Va xut kt qu ra mn hnh, va xut vo file.

*V d:

* ls l /etc | tee /root/list.txt

**Lnh TEE: Va xut kt qu ra mn hnh, va xut vo file.

*V d:

* ls l /etc | tee /root/list.txt

**cat & tac *head & tail *nl & wc, *od & hexdump *join, sort, tr *grep

**cat: Xem ni dung file *V d: Xem ni dung tp tin /etc/passwd *cat /etc/passwd *Cc tham s: * -n : nh s cc dng output * -b : khng tnh dng trng (blank) * -A : hin th k t xung dng *Lnh tac in ngc li vi lnh cat, xut dng

cui trc

** Lnh head: Xem cc dng u ca d liu. * V d: xem 4 dng u tp tin /etc/passwd * head -4 /etc/passwd HOC cat /etc/passwd | head -4

* Hoc xem 4 tp tin / th mc con u tin trong th mc / * ls l / | head -4

* Lnh tail: Xem cc dng cui ca d liu * V d: xem 5 dng cui ca tp tin /etc/passwd * tail -5 /etc/passwd HOC cat /etc/passwd | tail -5

* Xem ni dung tp tin /etc/passwd t dng th 4 n ht: * tail --lines=+4 /etc/passwd * hoc cat /etc/passwd | tail --lines=+4

* Ch : tail c thm tham s -f c cc file ng

** Syntax: wc [option] [files] * -l : m s dng

* -c hay m : m k t

* -w : m s t

*$ wc -l file1 - m s dng *$ wc file[123] - m 3 file *$ wc -c file1 - m s k t

**Lnh nl: nh s dng *V d: * ls l / | nl

*Xem danh sch cc files v c nh s dng *nl aaa.txt

**Syntax join [options] file1 file2 *tham s: -j field

*V d: *$ join j 1 file1 file2

*$ join j 1 file2 file1

** Syntax tr [options] [[string1 [string2]] * tham s : d xa, -s : thay th lp

* $ cat file1 | tr a-z A-Z - thng sang hoa * $ cat file1 | tr -d a - xa k t a * $ tr '[A-B]' '[a-b]'< file.txt hoa sang thng * $ tr ':' ' ' < /etc/passwd - thay : bng * $ cat file1 | tr -d abc - xa k t abc * [:lower:] ch thng * [:upper:] ch hoa * [:alnum:] ch ci hoc s * Ch : tr ch c 2 i s Cu hi: Xa k t a khi file a.txt, ri lu thnh file b.txt ?

**C php: *cut -d -f

*V d: C chui input *1;2;3;4;5;6

*Cn ct ra s 5 (trng th 5)

*echo 1;2;3;4;5;6 | cut -d; -f5

**C php: in ra trng th n *awk -F { print $n}

*Mc nh k t ngn cch l cc khong trng

*V d: C chui input *1;2;3;4;5;6

*Cn ct ra s 5 (trng th 5) *echo 1;2;3;4;5;6 | awk F; { print $5 }

**C php: in ra trng th n *awk -F { print $n}

*Mc nh k t ngn cch l cc khong trng

*V d: C chui input *1;2;3;4;5;6

*Cn ct ra s 5 (trng th 5) *echo 1;2;3;4;5;6 | awk F; { print $5 }

**Tm kim ni dung. C php: * grep [OPTION] PATTERN [FILE] * -i: Khng phn bit hoa thng * -n: Km theo s th t dng khi xut * -r: tm lp li trong th mc con * -v: tm nghch o * -w: tm nguyn t

*V d: * grep root /etc/passwd : tm nhng dng c t root trong file

/etc/passwd

* ls l /etc/ | grep conf : tm nhng file c cm t conf trong th mc /etc

** [abc]: k t a,b hoc k t c * [a-h]: mt k t trong khong a h * [^abc]: khng phi a,b,c * (ab|bc|cd): ab hoc bc hoc cd * ^: u 1 dng *$: cui 1 dng * . : mt k t bt k *S ln xut hin: * *: t 0 n n ln * +: t nht 1 ln

**find [path] [expression] *$ find / -name *.txt #Tm file c kiu txt trong th

mc /

*$ find /usr/local -type f : ch tm file

*$ find /usr/X11R6 -type d : ch tm th mc

*$ find . -perm 755 -a -type f : tm theo permission

**Shutdown: * init 0 *Hoc

*shutdown h now

*Restart: * init 6 *Hoc

*shutdown r now

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