Uhlobo lweS $ SHLVL lusetyenziselwa ukukuxelela ukuba uninzi kangakanani iigobols. Ukuba udidekile yile nto kulungele ukuqala ekuqaleni.
Yintoni iShell?
Igobolondo ithatha imiyalelo kwaye ibanikezela kwinkqubo yokusebenza ephantsi ukwenza. Kwiinkqubo ezininzi ze-Linux iprogram ye-shell ibizwa ngokuba yi-BASH (i-Bourne Again Shell) kodwa kukho ezinye zikhoyo kuquka i-C Shell (tcsh) kunye ne-shell KORN (ksh).
Indlela Yokufikelela I-Linux Shell
Ngokuqhelekileyo njengomsebenzisi usebenzisana neprogram yecolom ngokusebenzisa ukusetyenziswa kweprogram yokuqulunqa kwe- terminal njenge-XTerm, konsole okanye i-gnome-terminal.
Ukuba uqhuba umphathi weefestile ezifana ne-Openbox okanye i-desktop environment ezifana ne-GNOME okanye i-KDE uza kufumana umthumeli wokuphela kweminye kwimenyu okanye idatha. Kwiinkqubo ezininzi i-shortcut CTRL ALT kunye no-T iya kuvula iwindi yokugcina.
Ngenye indlela ungatshintshela kwenye i-tty (i-teletypewriter) enika ufikelelo oluchanekileyo kumgca wecolongo yomyalelo. Unokwenza oku ngokucindezela i-CTRL ALT kunye ne-F1 okanye i-CTRL ALT kunye ne-F2 njl.
Iyini iNqanaba leShell
Xa uqhuba umyalelo kwigobolondo ugijima kwinto ebizwa ngezinga legobolondo. Ngaphakathi kwegobolondo unokuvula enye igobolondo eyenza ibe yintsikhsi okanye ikhebhile evulekileyo.
Ngoko ke igobolondo lomzali liya kuqwalaselwa mhlawumbi kwinqaba ye-shell 1 kwaye igobolondo yengane iya kuba yinqabileyo yesi-2.
Indlela Yokubonisa I-Shell Level
Kumele kungabi ngothusayo kusekelwe kwinqaku le nqaku ebonisa ukuba ungayifumana njani iqela legobolthi osebenza kulo ngokusebenzisa i-variable ye-$ SHLVL.
Ukubona izinga legobolthi osebenza ngoku kuluhlu olulandelayo:
bhala i $ SHLVL
Kunomdla xa uqhuba umyalelo ongentla apha kwifestile yesigxina ungamangaliswa ukubona ukuba isiphumo sabuya si-2.
Ukuba kunjalo uqhuba umyalelo ofanayo usebenzisa i-tty ngoko umphumo ngowoku-1.
Kutheni le nto ungayicela? Kaloku i-desktop yendalo osebenzayo iyaqhutyelwa phezulu kwegobolondo. Igobolondo iya kuba yinqanaba 1. Nayiphi na ifowuni yokugcina ovula kuyo ngaphakathi kwimo yendawo yedesktop kufuneka ibe ngumntwana wegobolondo evule imo ye desktop kwaye ngoko igobolondo ayikwazi ukuqala nayiphi na inombolo ngaphandle kwe-2.
I-tty ayisebenzisi indawo yendawo yedesktop kwaye ngoko ke yinto nje yegobolondo yezinga 1.
Indlela yokudala i-Subshells
Indlela elula yokuvavanya umxholo wee-shells kunye ne-subshells ngolu hlobo lulandelayo. Vula ifowuni yokugcina kwaye uthayiphe oku kulandelayo:
bhala i $ SHLVL
Njengoko siyazi ukusuka kwiphepha lefayili kwinqanaba elincinci legobolthi li-2.
Ngoku kungaphakathi kwiphepha le window elilandelayo:
sh
Umyalelo we-sh uqobo uqhuba igobolondo edibeneyo oko kuthetha ukuba usebenzisa igobolondo ngaphakathi kwegobolondo okanye i-subshell.
Ukuba ngoku uthayipha oku kwakhona:
bhala i $ SHLVL
Uza kubona ukuba i-shell shell isetyenziswe kwi-3. Ukusebenza komyalelo sh ukusuka ngaphakathi kwe-subshell kuya kuvula i-subshell ye-subshell kwaye ngoko igobolithi iya kuba kwinqanaba 4.
Kutheni i-Shell Level ibalulekile?
Inqanaba lebhokbhile ibalulekile xa ucinga malunga nobubanzi bezinto ezikhoyo kwiempendulo zakho.
Masiqale ngento elula:
inja = i-maisie
bhekisa inja ye $
Ukuba uqhuba umyalelo ongentla apha kwi-shell, igama elithi maisie liza kuboniswa kwi window window.
Vula igobolondo entsha ngokuthayipha oku kulandelayo:
sh
Ukuba uqhuba lo myalelo uya kubona ukuba akukho nto ibuyiselwe yona:
bhekisa inja ye $
Kungenxa yokuba uguqulo lwenja ye-$ lufumaneka kuphela kwi-shell yezinga le-shell 2. Ukuba uthayipha ukuphuma ukuze uphume kwi-subshell kwaye usebenzise i-echo $ inja kwakhona igama elithi maisie liya kuboniswa kwakhona.
Kufanelekile ukucinga malunga nokuziphatha kwezinto ezikhoyo kwihlabathi.
Qala kwi window entsha kwaye uthayiphe oku kulandelayo:
Inja yokuthumela ngaphandle = i-maisie
bhekisa inja ye $
Njengoko ungalindela igama elithi maisie liboniswa. Ngoku vula i-subshell kwaye uthayiphe i-echo yenja yeenja kwakhona. Ngeli xesha uya kubona ukuba igama elithi maisie liyaboniswa nangona unesigxina.
Isizathu salokhu kukuba umyalelo wokuthumela ngaphandle wenza ihlabathi lehlabathi eliguquguqukayo. Ukutshintshwa kweenja zeerhafu kwi-subshell nokuba ngaba usebenzisa umyalelo wokuthumela ngaphandle akuchaphazeli kwiigobolondo zabazali.
Ngethemba ukuba kule ndawo unokubona ukuba ukwazi iqondo lebhokbhile osebenza kuyo linokubaluleka xa ubhala iincwadi zeempendulo.
Imizekelo endiyinike yona yinto elula kakhulu kodwa kuyinto eqhelekileyo kwiskripthi esisodwa sekhanda elibizwa ngokuba lelinye iqhosha le-shell ebizwa ngokuba yinye enye i-shell shell esebenza kumanqanaba ahlukeneyo ngoku. Ukwazi iqondo legobolongo lingaba luleke kakhulu.