Ngiyithola kanjani imigqa yokuqala eyi-10 ku-Unix?

Ukubheka imigqa embalwa yokuqala yefayela, thayipha igama lefayela lenhloko, lapho igama lefayela kuyigama lefayela ofuna ukulibuka, bese ucindezela . Ngokuzenzakalelayo, ikhanda likukhombisa imigqa yokuqala eyi-10 yefayela. Ungakushintsha lokhu ngokuthayipha igama lefayela elithi head -number, lapho inombolo iyinombolo yemigqa ofuna ukuyibona.

Ngiyithola kanjani imigqa yokuqala eyi-10 yefayela ku-Unix?

Thayipha umyalo wekhanda olandelayo ukuze ubonise imigqa yokuqala eyi-10 yefayela elibizwa ngokuthi “bar.txt”:

1. ikhanda -10 bar.txt.
2. ikhanda -20 bar.txt.
3. sed -n 1,10p /etc/group.
4. sed -n 1,20p /etc/group.
5. awk 'FNR <= 10' /etc/passwd.
6. awk 'FNR <= 20' /etc/passwd.
7. perl -ne'1..10 bese uphrinta' /etc/passwd.
8. perl -ne'1..20 bese uphrinta' /etc/passwd.

18 unyaka. 2018 г.

Uyihlanganisa kanjani imigqa yokuqala eyi-10?

ikhanda -n10 igama lefayela | grep ... ikhanda lizokhipha imigqa yokuqala eyi-10 (usebenzisa inketho ethi -n), bese ungaphayipha lokho okukhiphayo ku-grep . Ungasebenzisa umugqa olandelayo: ikhanda -n 10 /path/to/file | grep […]

Ngiwuthola kanjani umugqa wokuqala ku-Linux?

Ukugcina umugqa ngokwawo, sebenzisa i-syntax ye-var=$(command). Kulokhu, umugqa=$(awk 'NR==1 {print; phuma}' ifayela) . Ngomugqa olinganayo=$(sed -n '1p' ifayela) . izoshesha kancane njengoba ukufundwa kuwumyalo owakhelwe ngaphakathi we-bash.

Uthini umyalo wokulanda amarekhodi ayi-10 okuqala ngefayela?

Umyalo wekhanda, njengoba negama lisho, phrinta inombolo ephezulu engu-N yedatha yokokufaka okunikeziwe. Ngokuzenzakalelayo, iphrinta imigqa yokuqala eyi-10 yamafayela ashiwo. Uma kunikezwe igama lefayela elingaphezu kwelilodwa khona-ke idatha evela kufayela ngalinye yandulelwa igama lefayela layo.

Uyithola kanjani imigqa yokuqala eyi-10 yefayela?

Ukubheka imigqa embalwa yokuqala yefayela, thayipha igama lefayela lenhloko, lapho igama lefayela kuyigama lefayela ofuna ukulibuka, bese ucindezela . Ngokuzenzakalelayo, ikhanda likukhombisa imigqa yokuqala eyi-10 yefayela. Ungakushintsha lokhu ngokuthayipha igama lefayela elithi head -number, lapho inombolo iyinombolo yemigqa ofuna ukuyibona.

Ngiyithola kanjani imigqa yokugcina eyi-10 yefayela ku-Unix?

I-syntax yomyalo we-Linux tail

Umsila umyalo ophrinta inombolo yokugcina embalwa yemigqa (imigqa eyi-10 ngokuzenzakalelayo) yefayela elithile, bese uyanqamula. Isibonelo sokuqala: Ngokuzenzakalelayo “umsila” uphrinta imigqa yokugcina eyi-1 yefayela, bese uyaphuma. njengoba ubona, lokhu kuphrinta imigqa yokugcina eyi-10 ye/var/log/messages.

Uyihlanganisa kanjani imigqa embalwa?

Ku-BSD noma i-GNU grep ungasebenzisa -B num ukuze usethe ukuthi mingaki imigqa ngaphambi komdlalo kanye -Inani lenombolo yemigqa ngemva komdlalo. Uma ufuna inombolo efanayo yemigqa ngaphambi nangemuva ungasebenzisa -C num . Lokhu kuzobonisa imigqa emi-3 ngaphambi nangemuva kwemi-3.

Wenzani umyalo wekati?

Umyalo 'wekati' [okufushane kokuthi “concatenate”] ungomunye wemiyalo esetshenziswa kakhulu ku-Linux nakwamanye amasistimu wokusebenza. Umyalo wekati usivumela ukuthi sakhe amafayela owodwa noma amaningi, ukubuka okuqukethe ifayela, ukuhlanganisa amafayela futhi siqondise kabusha okukhiphayo kusiphetho noma amafayela.

Wenzani umyalo we-grep?

I-grep iyinsizakalo yomugqa womyalo yokusesha amasethi edatha yombhalo ongenalutho wemigqa ehambisana nesisho esivamile. Igama layo livela ku-ed command g/re/p (sesha emhlabeni wonke isisho esivamile bese uphrinta imigqa emeshayo), onomphumela ofanayo.

Ngiwufunda kanjani umugqa wokuqala wefayela?

Sebenzisa ifayela.

Vula ifayela kumodi yokufunda nge-syntax ene-open(igama lefayela, imodi) njengefayela: ngemodi ethi “r” . Ifayela lekholi. readline() ukuze uthole umugqa wokuqala wefayela futhi ugcine lokhu ku-variable first_line .

Kuyini ukusetshenziswa kwe-awk ku-Linux?

I-Awk iyinsiza eyenza umhleli akwazi ukubhala izinhlelo ezincane kodwa eziphumelelayo ngendlela yezitatimende ezichaza amaphethini ombhalo okufanele aseshwe kulayini ngamunye wedokhumenti kanye nesenzo okufanele sithathwe lapho okufanayo kutholakala ngaphakathi umugqa. I-Awk isetshenziswa kakhulu ukuskena iphethini nokucubungula.

Ngisifaka kanjani ikhodi ye-bash script?

Ungabhala Kanjani Iskripthi SeShell ku-Linux/Unix

1. Dala ifayela usebenzisa umhleli we-vi (noma yimuphi omunye umhleli). Qamba ifayela lombhalo elinesandiso. sh.
2. Qala iskripthi nge-#! /bin/sh.
3. Bhala ikhodi.
4. Londoloza ifayela lombhalo njenge-filename.sh.
5. Ukuze usebenzise uhlobo lombhalo bash filename.sh.

2 Mashi 2021 g.

Yimuphi umyalo osetshenziselwa ukukhomba amafayela?

Umyalo wefayela usebenzisa ifayela /etc/magic ukukhomba amafayela anenombolo yomlingo; okungukuthi, noma yiliphi ifayela eliqukethe inombolo noma iyunithi yezinhlamvu engashintshi ebonisa uhlobo. Lokhu kubonisa uhlobo lwefayela le-myfile (njengenkomba, idatha, umbhalo we-ASCII, umthombo wohlelo C, noma ingobo yomlando).

Yimuphi umyalo osetshenziselwa ukukopisha?

Umyalo ukopisha amafayela ekhompyutha usuka kolunye uhla lwemibhalo uye kolunye.
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kopisha (umyalo)

Uwuthola kanjani umugqa we-10 efayeleni lombhalo?

Ngezansi kunezindlela ezintathu ezinhle zokuthola umugqa we-nth wefayela ku-Linux.

1. ikhanda / umsila. Ukusebenzisa nje inhlanganisela yemiyalo yekhanda nomsila cishe kuyindlela elula kakhulu. …
2. sed. Kunezindlela ezimbalwa ezinhle zokwenza lokhu nge-sed. …
3. awu. I-awk ine-NR eyakhelwe ngaphakathi egcina umkhondo wezinombolo zemigqa yefayela/yokusakaza.