8 Uchebnye materialy po FTP i spisok serverov

Obratite vnimanie na to, chto v "ekranah", privodimyh nizhe, ya lish' pokazyvayu naibolee sushchestvennuyu informaciyu, tak chto to, chto vy mozhete uvidet' na real'nom ekrane, mozhet otlichat'sya.

Dlya zapuska ftp i ustanovleniya svyazi s serverom prosto ispol'zujte komandu

    ftp <hostname>

gde <hostname> - imya servera, s kotorym vy svyazyvaetes'. Naprimer, dlya svyazi s mificheskim serverom shoop.vpizza.com mozhno ispol'zovat' komandu

    ftp shoop.vpizza.com

Kogda zapuskaetsya ftp, my mozhem uvidet' chto-to vrode

    Connected to shoop.vpizza.com.
    220 Shoop.vpizza.com FTPD ready at 15 Dec 1992 08:20:42 EDT
    Name (shoop.vpizza.com:mdw):

Zdes' ftp prosit nas vvesti imya (Name) pol'zovatelya, pod kotorym my hotim vojti na server shoop.vpizza.com. Po umolchaniyu zdes' "mdw", chto sluzhit moim imenem pol'zovatelya dlya FTP-vhoda. Poskol'ku u menya net account (prim. perevodchika: ne otkryt schet, a tochnee (no dal'she ot teksta) - ne zaregistrirovan v kachestve pol'zovatelya) na shoop.vpizza.com, ya ne mogu vojti pod svoim imenem. Vmesto etogo, chtoby vojti na obshchedostupnyj FTP-server vy vhodite kak anonymous (anonim) i soobshchaete svoj adres e-mail (esli on u vas est') v kachestve parolya. To est' nam sleduet vvesti

    Name (shoop.vpizza.com:mdw):  anonymous
    331-Guest login ok, send e-mail address as password.
    Password:  mdw@sunsite.unc.edu
    230- Welcome to shoop.vpizza.com.
    230- Virtual Pizza Delivery[tm]:  Download pizza in  30 cycles
    or less
    230- or you get it FREE!
    ftp>

Razumeetsya, vam sleduet soobshchat' svoj e-mail adres vmesto moego, on ne budet otobrazhat'sya na ekrane pri vashem vvode (poskol'ku on vvoditsya pod "vyveskoj" parolya). ftp dolzhen pozvolit' nam vojti i my budem imet' vozmozhnost' skachivat' programmy.

O'kej, my voshli. ftp> - eto nasha podskazka, teper' programma ftp zhdet vvoda komand. Est' neskol'ko osnovnyh komand, kotorye vam nado znat'. Prezhde vsego, komandy

    ls <file>

i

    dir <file>

obe dayut spisok fajlov (gde <file> - neobyazatel'nyj argument, ukazyvayushchij, kakoj spisok vyvesti). Raznica v tom, chto ls obychno vydaet korotkij spisok, a dir - dlinnyj (to est' s bol'shej informaciej otnositel'no razmera fajlov, daty modifikacii i t.p.). Komanda

    cd <directory>

peremestit "vas" v ukazannyj katalog (tochno takzhe, kak komanda cd v UNIX ili MS-DOS). Vy mozhete ispol'zovat' komandu

    cdup

dlya perehoda v roditel'skij (nahodyashchijsya vyshe) katalog

Komanda

    help <command>

dast vam podskazku po ukazannoj komande ftp (takoj kak ls ili cd). Esli komanda ne ukazana, ftp vydast spisok vseh dostupnyh komand. Esli my vvedem teper' dir, my uvidim nachal'nyj katalog nashego mestonahozhdeniya.

    ftp> dir
    200 PORT command successful.
    150 Opening ASCII mode data connection for /bin/ls.
    total 1337

    dr-xr-xr-x  2 root     wheel         512 Aug 13 13:55 bin
    drwxr-xr-x  2 root     wheel         512 Aug 13 13:58 dev
    drwxr-xr-x  2 root     wheel         512 Jan 25 17:35 etc
    drwxr-xr-x 19 root     wheel        1024 Jan 27 21:39 pub
    drwxrwx-wx  4 root     ftp-admi     1024 Feb  6 22:10 uploads
    drwxr-xr-x  3 root     wheel         512 Mar 11  1992 usr

    226 Transfer complete.
    921 bytes received in 0.24 seconds (3.7 Kbytes/s)
    ftp>

Kazhdaya iz etih strok predstavlyaet katalog, a ne otdel'nyj fajl, kotoryj my mozhem skachat' (na eto ukazyvaet simvol "d" v pervoj pozicii spiska). Na bol'shinstve arhivnyh FTP-serverov obshchedostupnye programmy nahodyatsya pod katalogom /pub, tak chto davajte tuda i pojdem.

    ftp> cd pub
    ftp> dir
    200 PORT command successful.
    150 ASCII data connection  for /bin/ls (128.84.181.1,4525)  (0
    bytes).
    total 846

    -rw-r--r--  1 root   staff     1433 Jul 12  1988 README
    -r--r--r--  1 3807   staff    15586 May 13  1991  US-DOMAIN.TXT.2
    -rw-r--r--  1 539    staff    52664 Feb 20  1991 altenergy.avail
    -r--r--r--  1 65534  65534    56456 Dec 17  1990 ataxx.tar.Z
    -rw-r--r--  1 root   other  2013041 Jul  3  1991 gesyps.tar.Z
    -rw-r--r--  1 432    staff    41831 Jan 30  1989 gnexe.arc
    -rw-rw-rw-  1 615    staff    50315 Apr 16  1992 linpack.tar.Z
    -r--r--r--  1 root   wheel    12168 Dec 25  1990 localtime.o
    -rw-r--r--  1 root   staff     7035 Aug 27  1986 manualslist.tblms
    drwxr-xr-x  2 2195   staff      512 Mar 10 00:48 mdw
    -rw-r--r--  1 root   staff     5593 Jul 19  1988 t.out.h

    226 ASCII Transfer complete.
    2443 bytes received in 0.35 seconds (6.8 Kbytes/s)
    ftp>

Zdes' my mozhem videt' ryad (interesnyh?) fajlov, odin iz kotoryh nazyvaetsya README, kotoryj nam sleduet skachat' (bol'shinstvo FTP-serverov imeet fajl README v kataloge /pub).

Pered skachivaniem fajlov sleduet obratit' vnimanie na

• Vklyuchite vyvod hesh-metok. Hesh-metki vyvodyatsya na ekran kak peredavaemye fajly; oni informiruyut o peredannyh ob'emah i chto peredacha ne zavisla (tak chto vy ne budete sidet' minut 20, polagaya, chto vy vse eshche skachivaete fajl). V obshchem sluchae hesh-metka poyavlyaetsya, kak simvol reshetki (#), kotoryj pechataetsya cherez kazhdye 1024 ili 8192 peredannyh bajt, v zavisimosti ot sistemy.

  Vklyuchenie hesh-metok osushchestvlyaetsya komandoj

          ftp> hash
          Hash mark printing on (8192 bytes/hash mark).
          ftp>
  

• Opredelite tip fajla, kotoryj vy skachivaete. FTP razlichaet dva tipa fajlov: binarnye (dvoichnye) i tekstovye. Bol'shinstvo fajlov, kotorye vy budete skachivat' - binarnye. |to programmy, skompressirovannye fajly, arhivirovannye fajly i t.p. No est' nemalo i tekstovyh fajlov (vrode README).

  Pochemu tip fajla imeet znachenie? Tol'ko potomu, chto na nekotoryh sistemah (takih, kak MS-DOS), opredelennye simvoly tekstovogo fajla, vrode vozvrata karetki, dolzhny byt' preobrazovany tak, chtoby fajl byl chitaem. A pri peredache binarnyh fajlov nikakih preobrazovanij ne osushchestvlyaetsya - fajl prosto peredaetsya bajt za bajtom.

  Komandy bin i ascii ispol'zuyutsya dlya perevoda sootvetstvenno v binarnyj rezhim peredachi fajlov i tekstovyj sootvetstvenno. Esli voznikayut somneniya - ispol'zujte binarnyj rezhim. Esli vy popytaetes' peredat' binarnyj fajl v tekstovom rezhime, fajl budet isporchen pri peredache do polnoj bespoleznosti. (|to odna iz populyarnejshih oshibok na nachal'nyh etapah ispol'zovaniya FTP). No razumeetsya, vy mozhete ispol'zovat' tekstovyj rezhim dlya peredachi normal'nyh tekstovyh fajlov (ch'i imena chasto zakanchivayutsya na .txt).

  Naprimer, my skachivaem fajl README kotoryj, skoree vsego, tekstovyj tak chto my ispol'zuem komandu

          ftp> ascii
          200 Type set to A.
          ftp>
  

• Ustanovite svoj mestnyj katalog. Vash mestnyj katalog, eto katalog vashej sistemy, kuda vy hotite v konechnom schete skachat' fajly. V to vremya kak komanda cd menyaet katalog udalennoj mashiny (mashiny, na kotoruyu vy voshli po FTP), komanda lcd menyaet mestnyj (l-local) katalog.

  Naprimer, chtoby ustanovit' mestnyj katalog /home/db/mdw/tmp, ispol'zujte komandu

          ftp> lcd /home/db/mdw/tmp
          Local directory now /home/db/mdw/tmp
          ftp>
  

Teper' vy dejstvitel'no gotovy skachivat' fajly. Komanda

    get <remote-name> <local-name>

ispol'zuetsya imenno dlya etogo, gde <remote-name> imya fajla na udalennoj mashine, a <local-name> - imya, kotoroe vy hotite dat' fajlu na vashej mashine. <local-name> - neobyazatel'nyj argument; po umolchaniyu imya mestnogo fajla to zhe, chto i u skachivaemogo fajla. No, esli naprimer vy skachivaete fajl README, i u vas uzhe est' fajl s imenem README v etom kataloge, vam sleduet dat' drugoe imya dlya <local-filename>, chtoby ne zateret' sushchestvuyushchij. Naprimer, dlya skachivaniya fajla README my prosto ispol'zuem

    ftp> get README
    200 PORT command successful.
    150 ASCII data connection for README (128.84.181.1,4527) (1433
    bytes).
    #
    226 ASCII Transfer complete.
    local:  README remote:  README
    1493 bytes received in 0.03 seconds (49 Kbytes/s)
    ftp>

Dlya prekrashcheniya FTP-sessii prosto ispol'zujte komandu

    quit

Komanda

    close

mozhet ispol'zovat'sya dlya zakrytiya svyazi s dannym FTP-serverom; komanda open mozhet byt' posle etogo ispol'zovana dlya nachala sessii s drugim serverom (bez vyhoda iz programmy FTP).

    ftp> close
    221 Goodbye.
    ftp> quit

ftpmail - eto servis, kotoryj pozvolyaet poluchit' fajly iz FTP-arhiva cherez elektronnuyu pochtu Internet. Esli u vas net pryamogo vyhoda na Internet, no est' vozmozhnost' posylat' pis'ma v Internet (naprimer, iz CompuServe), ftpmail - eto horoshij sposob poluchit' fajly iz arhivov FTP-serverov. K sozhaleniyu, ftpmail mozhet byt' medlennym, osobenno pri peresylke bol'shih ob'emov. Pered popytkoj skachat' bol'shoe chislo programm s ispol'zovaniem ftpmail, ubedites', chto oblast' spullinga vashej mail budet sposobna spravit'sya s takimi ob'emami vhodnogo trafika. Vo mnogih sistemah est' ogranicheniya na ob'em prihodyashchej elektronnoj pochty (prim. perevodchika: ogranicheniya mogut byt' kak na ob'em otdel'nogo fajla, tak i na obshchee chislo prinimaemyh (razmeshchaemyh vo vhodnom spule) fajlov). Tak chto rukovodstvujtes' zdravym smyslom.

sunsite.unc.edu - odin iz glavnyh arhivnyh Linux FTP-serverov, imeet takzhe ftpmail-server. Dlya togo, chtoby vospol'zovat'sya etim servisom, poshlite pis'mo po adresu:

    ftpmail@sunsite.unc.edu

A v pis'me tol'ko odno slovo

    help

V rezul'tate vy poluchite v otvet spisok komand ftpmail i kratkuyu instrukciyu po pol'zovaniyu sistemoj.

Naprimer, dlya polucheniya spiska fajlov sunsite.unc.edu, poshlite pis'mo po vysheukazannomu adresu so sleduyushchim tekstom:

    open sunsite.unc.edu
    cd /pub/Linux
    dir
    quit

Vy mozhete ispol'zovat' ftpmail dlya svyazi s arhivom FTP-servera; i eto ne ogranichivaetsya lish' sunsite.unc.edu. V sleduyushchem razdele privoditsya spisok Linux FTP-arhivov.

Tablica C.1 - eto spisok naibolee izvestnyh arhivnyh FTP-serverov, kotorye hranyat pakety programm dlya Linux. Imejte v vidu, chto mnogie drugie servera imeyut zerkal'nye otobrazheniya mnogih iz etih arhivov, tak chto skoree vsego vy najdete nuzhnoe vam na serverah, otsutstvuyushchih v etom spiske.

tsx-11.mit.edu, sunsite.unc.edu i nic.funet.fi - eto "dom rodnoj" dlya Linux, gde vy mozhete najti bol'shinstvo novyh programm. Bol'shinstvo drugih serverov iz spiska zerkal'no otobrazhayut nekotoruyu kombinaciyu iz etih treh. Dlya umen'sheniya setevogo trafika vybirajte server, kotoryj blizhe k vam geograficheski.

 Imya servera                    IP adres          Katalog

 tsx-11.mit.edu                 18.172.1.2       /pub/linux
 sunsite.unc.edu                152.2.22.81      /pub/Linux
 nic.funet.fi                   128.214.6.100    /pub/OS/Linux
 ftp.mcc.ac.uk                  130.88.200.7     /pub/linux
 fgb1.fgb.mw.tu-muenchen.de     129.187.200.1    /pub/linux
 ftp.informatik.tu-muenchen.de  131.159.0.110    /pub/Linux
 ftp.dfv.rwth-aachen.de         137.226.4.105    /pub/linux
 ftp.informatik.rwth-aachen.de  137.226.112.172  /pub/Linux
 ftp.ibp.fr                     132.227.60.2     /pub/linux
 kirk.bu.oz.au                  131.244.1.1      /pub/OS/Linux
 ftp.uu.net                     137.39.1.9       /systems/unix/linux
 wuarchive.wustl.edu            128.252.135.4    /systems/linux
 ftp.win.tue.nl                 131.155.70.100   /pub/linux
 ftp.ibr.cs.tu-bs.de            134.169.34.15    /pub/os/linux
 ftp.denet.dk                   129.142.6.74     /pub/OS/linux

                  Tablica C.1: FTP-servery Linux