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ls

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ls la mot lenh dung de liet ke cac file cua he dieu hanh Unix hoac giong Unix. ls duoc mo ta boi POSIX va Single UNIX Specification.

Lich su

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Cong cu ls ban dau xuat hien trong phien ban AT&T Unix. Ten no duoc bat nguon tu lenh list segments trong Multics, he thong xem memory segment va file la nhu nhau. Ngay nay, hai phien ban pho bien nhat cua ls la cua Free Software Foundation (mot phan thuoc goi coreutils cua GNU) va phien ban cua BSD, nhu FreeBSD, OpenBSD, NetBSD, va Darwin cua Apple Computer. Ca hai deu la phan mem mien phi va ma nguon mo.

Cach hoat dong

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He dieu hanh Unix va tua Unix co mot khai niem la thu muc lam viec hien tai, nghia la vi tri hien tai trong he thong thu bac cua cay thu muc.

Khi goi khong co tham so, ls liet ke cac file trong thu muc lam viec hien tai. Khi goi ls va chi dinh mot thu muc khac, no se liet ke cac file trong thu muc do. Nguoi dung co the chi dinh nhieu file va thu muc can liet ke, no se liet ke tat ca nhung thu muc do.

File bat dau bang ky tu "." se khong hien ra, tru khi nguoi dung goi voi tham so -a hoac file duoc nguoi dung chi dinh mot cach tuong minh.

Neu goi khong co tham so, ls se hien ra dinh dang thu gon toi thieu. Dinh dang nay kho dung de xac dinh loai, quyen va kich thuoc file. Nhung tham so thong dung nhat de hien cac thong tin hoac thay doi danh sach file:

  • -l long format, hien loai file Unix, quyen, so luong hard link, nguoi so huu, nhom so huu, kich thuoc, ngay thay doi, va ten file.
  • -F gan them ky tu sau ten file de cho biet loai file. Vi du, * cho file thuc thi duoc, hoac / cho thu muc. File binh thuong khong gan them ky tu nao.
  • -a liet ke tat ca file trong thu muc, ke ca file bat dau bang dau ".". Mac nhien, cac file nay khong duoc liet ke.
  • -R liet ke de quy cac thu muc con. Lenh ls -R / se hien tat ca cac file trong he thong.
  • -d chi hien thu muc chi dinh hoac symbolic link, chu khong hien danh sach cac file trong thu muc va dich cua symbolic link.

O mot so moi truong, khi dua tham so --color (doi voi phien ban GNU ls) hoac -G (FreeBSD ls), ls se to mau cac loai file khac nhau bang cac mau khac nhau, thay vi bang cach them ky tu vao phia sau nhu tham so -F. De xac dinh mau cho file, GNU ls kiem tra loai file, quyen va phan mo rong cua file, trong khi do FreeBSD ls chi kiem tra loai file va quyen.

Khi su dung tham so hien mau, ket qua co the giong nhu:

brw-r--r-- 1 unixguy staff 64, 64 Jan 27 05:52 block
crw-r--r-- 1 unixguy staff 64, 255 Jan 26 13:57 character
-rw-r--r-- 1 unixguy staff 290 Jan 26 14:08 compressed.gz
-rw-r--r-- 1 unixguy staff 331836 Jan 26 14:06 data.ppm
drwxrwx--x 2 unixguy staff 48 Jan 26 11:28 directory
-rwxrwx--x 1 unixguy staff 29 Jan 26 14:03 executable
prw-r--r-- 1 unixguy staff 0 Jan 26 11:50 fifo
lrwxrwxrwx 1 unixguy staff 3 Jan 26 11:44 link -> dir
-rw-rw---- 1 unixguy staff 217 Jan 26 14:08 regularfile

ls co rat nhieu tham so. No la mot cong cu dung thuong xuyen de xu ly he thong file thong qua giao dien dong lenh.

Tren mot so he thong (nhu PCLinuxOS), ls co mot alias chi la l. Nhieu he thong khac cung alias ls -l thanh ll.

Vi du cach su dung

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Vi du duoi day cho ket qua cua lenh ls voi hai tham so khac nhau:

$ pwd
/home/fred
$ ls -l
drwxr--r-- 1 fred editors 4096 drafts
-rw-r--r-- 1 fred editors 30405 edition-32
-r-xr-xr-x 1 fred fred 8460 edit
$ ls -F
drafts/
edition-32
edit*

Trong vi du nay, nguoi dung fred co thu muc ten la drafts, mot file binh thuong ten edition-32, va mot file thuc thi ten edit trong thu muc nha. ls cho biet quyen truy xuat cua nguoi dung doi voi cac file trong thu muc. O cot dau tien se liet ke quyen cho ba nhom: nguoi so huu (u), nhom so huu (g), va nguoi khac (o)

drwxr--r-- 1 fred editors 4096 Mar 1 2007 drafts

duoc anh xa vao

duuugggooo (so luong hard link) nguoi_so_huu nhom_so_huu kich_thuoc ngay_tao ten

Co nghia la drafts la thu muc, nguoi so huu co quyen rwx (liet ke, thay doi va chuyen den), nhom so huu co quyen r (liet ke), va nhung nguoi khac co quyen r (liet ke).

Xem them

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Tham khao

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Lien ket ngoai

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