Ngokutsho kwe-Wikipedia, i-metacharacter nayiphi na impawu enentsingiselo ekhethekileyo, njenge-carat (^), uphawu lweedola (i-dollar) okanye i-asterisk (*).
Ngokubhekiselele kwiLuxux, kukho inani elincinane lala ma-metacharacters kunye neentsingiselo zabo ziyahlukahluka kuxhomekeke kumyalelo owodwa okanye inkqubo osebenza ngayo.
I-Stop Stop njenge-Metacharacter (.)
Ukumisa okuzithobayo kusetyenziselwa ukunikela isikhundla samanje xa uqhuba imiyalelo efana ne- cd , fumana okanye sh kodwa ngaphakathi kwezicelo ezifana ne- awk , grep kwaye usebenzise it is used to denote any character.
Njengomzekelo, umyalelo olandelayo uzakufumana zonke iifayile zefayile kwifolda yangoku kunye nezantsi.
fumana. -name * .mp3
Ukuba uqhuba loo myalelo kuwe ubonisa isixhobo sokusebenza (pwd) kwaye ngokuqinisekileyo uza kufumana iziphumo, ucinga ukuba ugcina iifayile zakho kwiifolda zomculo ngaphakathi kwifolda yakho yasekhaya.
Ngoku jonga lo myalelo:
ps -ef | grep f..efox
I-ps iyalula uluhlu lweenkqubo ezisebenzayo kwikhompyutha yakho. Umyalelo we-grep uthatha imigca yokufaka kunye nokukhangela iphethini.
Ngako-ke umyalelo we-ps -ef ufumana uluhlu lweenkqubo zokusebenza kwaye unikezela kwi-grep efuna naluphi na umgca kuloluhlu olune-ffox apho. kunokuthetha nayiphi na impawu.
Ukuba unomlilo osebenzayo uzakufumana umdlalo. Ngokufanayo, ukuba unenkqubo ebizwa ngokuba yi-fonefox okanye i-freefox esebenzayo iya kubuyiselwa kwakhona.
I-asterisk njenge-metacharacter (*)
I-asterisk iyimetacharacter eyaziwa ngokubanzi emhlabeni jikelele kwaye isetyenziselwa ukuthatha 0 okanye ngaphezulu xa ifuna iphethini.
Umzekelo:
fumana. -name * .mp3
I * .mp3 ubuyisela umdlalo naluphi na igama lefayile eliphela kwi-.mp3. Ngokufanayo, ndingawusebenzisa i-asterisk ngomyalelo we-grep njengoko oku kulandelayo kubonisa:
ps -ef | grep F * efox
Kubalulekile ukuba uqaphele ukuba le nto ihluke kancinane kuba i-asterisk ithetha i-zero okanye ngaphezulu kunye nokufumana umlilo, ubuso be-facefox kunye ne-fonefox kunokufumana i-flutefox, i-ferretfox kunye ne-fefox nje.
I-Carat Njenge-Metacharacter (^)
I-carat (^) isetyenziswe ukubonisa ukuqala komgca okanye umtya. Ngoko isetyenziswe njani?
Umyalelo we-ls usetyenziswa ukuluhlu zonke iifayile kwifolda ngale ndlela:
ls
Ukuba ufuna ukwazi zonke iifayile kwifolda eqala ngentambo ethile "njenge-gnome" kwaye i-carat ingasetyenziselwa ukucacisa loo mtya.
Umzekelo:
ls | griome ^ gnome
Qaphela ukuba oku kuphela kuluhlu lweefayili eziqala ngegama. Ukuba ufuna iifayile ezinomnxeba kwigama legama apho uya kuphinda ubuyele kwakhona kwi-asterisk.
Kulo mzekelo ungentla, i-ls ibuyisela uludwe lwamagama eefayile kunye nokudlulayo okuluhlu kwi-grap esetyenziselwa ukufanisa iphethini. I-grep iyazi ukuba isimboli se-carat sithetha nantoni na eqala ngabalinganiswa abayilandelayo kwaye kule meko, yinto enhle.
I-Dollar Symbol Njenge-Metacharacter (i-$)
Isimboli seli dola sinokuthetha ezininzi njengemetacharacter ngaphakathi kwe-Linux.
Xa isetyenziselwa ukufanisa iipateni ithetha okuchasene ne-carat kwaye ichaza nayiphi na iphethini ephela ngomtya othile.
Umzekelo:
ls | grep png $
Olu dwelisa zonke iifayile eziphela nge-png.
Isimboli se dola sisetyenziselwa ukufikelela kwimimandla engqinelanayo ngaphakathi kwegobolish bash.
Umzekelo:
inja ye-export = molly
bhekisa inja ye $
Inja yokuthumela impahla = i-molly yenza inguquko yendawo ebizwa ngokuthi inja kwaye ibeka ixabiso layo kwi-molly. Ukufikelela kwiimeko ezichaseneyo zendawo ifayile isetyenziswa. Ngama-dollar isimboli se-dog statement isitatimende sibonisa i-molly kodwa ngaphandle kwayo, isitatimende senja ye-echo sibonisa nje inja yegama.
Ukusuka kwiMetacharacters
Maxa wambi awufuni ukuba i-metacharacter ibe nenjongo ekhethekileyo. Kuthekani ukuba unayo ifayile ebizwa f.refox kunye nefayile ebizwa ngokuba ngumlilo.
Ngoku jonga umyalelo olandelayo:
ls | grep f.refox
Ucinga ukuba ubuyisela ntoni? Bobabini f.refox kunye ne-firefox babuyiselwa kuba bobabini bafanisa iphethini.
Ukubuyela kuphela f.refox uza kufuneka ubalekele ukuyeka ngokupheleleyo ukuze uthethe ukuyeka ngokupheleleyo njengoko kulandelayo:
ls | grep f \\. refox
IiMetacharacters eziqhelekileyo kunye nokuThetha kwabo
| Umntu | Nentsingiselo |
| . | Nawuphi na umlingiswa |
| * | Zero okanye abalinganiswa |
| ^ | Qhathanisa nayiphi na umgca okanye umtya oqala ngephethini (ie ^ gnome) |
| $ | Qhathanisa nayiphi na umgca okanye umtya ophela ngephethini (oko kukuthi i-gnome $) |
| \ | Ukhupha umlingisi olandelayo ukususa intsingiselo yakhe ekhethekileyo |
| [] | Ukuchonga omnye uluhlu okanye uluhlu (okt ["abc", "def"] okanye [1..9] |
| + | Match one okanye ngaphezulu ezandulelayo (ie grep a +) |
| ? | Ukutshatshana kwenzeni okanye enye eyandulelayo |