Linux程序设计大报告Word格式文档下载.docx

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Linux程序设计大报告Word格式文档下载.docx

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Linux程序设计大报告Word格式文档下载.docx

6.#Thisprogramisfreesoftware;

youcanredistributeitand/ormodifyit

7.#underthetermsoftheGNUGeneralPublicLicenseaspublishedbythe

8.#FreeSoftwareFoundation;

eitherversion2oftheLicense,or（atyour

9.#option）anylaterversion.

10.

11.#Thisprogramisdistributedinthehopesthatitwillbeuseful,but

12.#WITHOUTANYWARRANTY;

withouteventheimpliedwarrantyof

13.#MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.SeetheGNUGeneral

14.#PublicLicenseformoredetails.

15.

16.#YoushouldhavereceivedacopyoftheGNUGeneralPublicLicensealong

17.#withthisprogram;

ifnot,writetotheFreeSoftwareFoundation,Inc.

18.#675MassAve,Cambridge,MA02139,USA.

19.

20.#Thefirstthingtodoistoensurethatsomeglobalvariablesthatwe'

llbeusing

21.#throughoutthescriptaresetup.Wesetthetitleandtrackfilesandatemporaryfile.

22.#WealsotrapCtrl-C,soourtemporaryfileisremovediftheuserinterruptsthescript.

23.

24.menu_choice="

25.current_cd="

26.title_file="

title.cdb"

27.tracks_file="

tracks.cdb"

28.temp_file=/tmp/cdb.$$

29.trap'

rm-f$temp_file'

EXIT

30.

31.#Nowwedefineourfunctions,sothatthescript,executingfromthetopline,canfind

32.#allthefunctiondefinitionsbeforeweattempttocallanyofthemforthefirsttime.

33.#Toavoidrewritingthesamecodeinseveralplaces,thefirsttwofunctionsaresimple

34.#utilities.

35.

36.get_return（）{

37.echo-e"

Pressreturn\c"

38.readx

39.return0

40.}

41.

42.get_confirm（）{

43.echo-e"

Areyousure?

\c"

44.whiletrue

45.do

46.readx

47.case"

$x"

48.y|yes|Y|Yes|YES）

49.return0;

;

50.n|no|N|No|NO）

51.echo

52.echo"

Cancelled"

53.return1;

54.*）echo"

Pleaseenteryesorno"

;

55.esac

56.done

57.}

58.

59.#Here,wecometothemainmenufunction,set_menu_choice.

60.#Thecontentsofthemenuvarydynamically,withextraoptionsbeingaddedifaCDentry

61.#hasbeenselected.Notethatecho-emaynotbeportabletosomeshells.

62.

63.set_menu_choice（）{

64.clear

65.echo"

Options:

66.echo

67.echo"

a）AddnewCD"

68.echo"

f）FindCD"

69.echo"

c）CounttheCDsandtracksinthecatalog"

70.if["

$cdcatnum"

];

then

71.echo"

l）Listtrackson$cdtitle"

72.echo"

r）Remove$cdtitle"

73.echo"

u）Updatetrackinformationfor$cdtitle"

74.fi

75.echo"

q）Quit"

76.echo

77.echo-e"

Pleaseenterchoicethenpressreturn\c"

78.readmenu_choice

79.return

80.}

81.

82.#Twomoreveryshortfunctions,insert_titleandinsert_trackforaddingtothedatabasefiles.

83.#Thoughsomepeoplehateone-linerslikethese,theyhelpmakeotherfunctionsclearer

84.#Theyarefollowedbythelargeradd_record_trackfunctionthatusesthem.

85.#Thisfunctionusespatternmatchingtoensurenocommasareentered（sincewe'

reusingcommas

86.#asafieldseparator）,andalsoarithmeticoperationstoincrementthecurrenttracknumber

87.#astracksareentered.

88.

89.insert_title（）{

90.echo$*>

$title_file

91.return

92.}

93.

94.insert_track（）{

95.echo$*>

$tracks_file

96.return

97.}

98.

99.add_record_tracks（）{

100.echo"

EntertrackinformationforthisCD"

101.echo"

Whennomoretracksenterq"

102.cdtrack=1

103.cdttitle="

104.while["

$cdttitle"

]

105.do

106.echo-e"

Track$cdtrack,tracktitle?

107.readtmp

108.cdttitle=${tmp%%,*}

109.if["

$tmp"

110.echo"

Sorry,nocommasallowed"

111.continue

112.fi

113.if[-n"

];

114.if["

115.insert_track$cdcatnum,$cdtrack,$cdttitle

116.fi

117.else

118.cdtrack=$（（cdtrack-1））

119.fi

120.cdtrack=$（（cdtrack+1））

121.done

122.}

123.

124.#Theadd_recordsfunctionallowsentryofthemainCDinformationforanewCD.

125.

126.add_records（）{

127.#Promptfortheinitialinformation

128.

129.echo-e"

Entercatalogname\c"

130.readtmp

131.cdcatnum=${tmp%%,*}

132.

133.echo-e"

Entertitle\c"

134.readtmp

135.cdtitle=${tmp%%,*}

136.

137.echo-e"

Entertype\c"

138.readtmp

139.cdtype=${tmp%%,*}

140.

141.echo-e"

Enterartist/composer\c"

142.readtmp

143.cdac=${tmp%%,*}

144.

145.#Checkthattheywanttoentertheinformation

146.

147.echoAbouttoaddnewentry

148.echo"

$cdcatnum$cdtitle$cdtype$cdac"

149.

150.#Ifconfirmedthenappendittothetitlesfile

151.

152.ifget_confirm;

153.insert_title$cdcatnum,$cdtitle,$cdtype,$cdac

154.add_record_tracks

155.else

156.remove_records

157.fi

158.

159.return

160.}

161.

162.#Thefind_cdfunctionsearchesforthecatalognametextintheCDtitlefile,usingthe

163.#grepcommand.Weneedtoknowhowmanytimesthestringwasfound,butgreponlyreturns

164.#avaluetellingusifitmatchedzerotimesormany.Togetaroundthis,westorethe

165.#outputinafile,whichwillhaveonelinepermatch,thencountthelinesinthefile.

166.#Thewordcountcommand,wc,haswhitespaceinitsoutput,separatingthenumberoflines,

167.#wordsandcharactersinthefile.Weusethe$（wc-l$temp_file）notationtoextractthe

168.#firstparameterfromtheoutputtosetthelinesfoundvariable.Ifwewantedanother,

169.#laterparameterwewouldusethesetcommandtosettheshell'

sparametervariablesto

170.#thecommandoutput.

171.#WechangetheIFS（InternalFieldSeparator）toa,（comma）,sowecanseparatethe

172.#comma-delimitedfields.Analternativecommandiscut.

173.

174.find_cd（）{

175.if["

$1"

176.asklist=n

177.else

178.asklist=y

179.fi

180.cdcatnum="

181.echo-e"

EnterastringtosearchforintheCDtitles\c"

182.readsearchstr

183.if["

$searchstr"

184.return0

185.fi

186.

187.grep"

$title_file>

$temp_file

188.

189.set$（wc-l$temp_file）

190.linesfound=$1

191.

192.case"

$linesfound"

193.0）echo"

Sorry,nothingfound"

194.get_return

195.return0

196.;

197.1）;

198.2）echo"

Sorry,notunique."

199.echo"

Foundthefollowing"

200.cat$temp_file

201.get_return

202.return0

203.esac

204.

205.IFS="

206.readcdcatnumcdtitlecdtypecdac<

207.IFS="

208.

209.if[-z"

210.echo"

Sorry,couldnotextractcatalogfieldfrom$temp_file"

211.get_return

212.return0

213.fi

214.

215.echo

216.echoCatalognumber:

$cdcatnum

217.echoTitle:

$cdtitle

218.echoType:

$cdtype

219.echoArtist/Composer:

$cdac

220.echo

221.get_return

222.

223.if["

$asklist"

224.echo-e"

ViewtracksforthisCD?

225.readx

226.if["

227.echo

228.list_tracks

229.echo

230.fi

231.fi

232.return1

233.}

234.

235.#update_cdallowsustore-enterinformationforaCD.Noticethatwesearch（grep）

236.#forlinesthatstart（^）withthe$cdcatnumfollowedbya,,andthatweneedtowrap

237.#theexpansionof$cdcatnumin{}sowecansearchfora,withnowhitespacebetween

238.#itandthecataloguenumber.Thisfunctionalsouses{}toenclosemultiplestatements

239.#tobeexecutedifget_confirmreturnstrue.

240.

241.update_cd（）{

242.if[-z"

243.echo"

YoumustselectaCDfirst"

244.find_cdn

245.fi

246.if[-n"

247.echo"

Currenttracksare:

248.list_tracks

249.echo

250.echo"

Thiswillre-enterthetracksfor$cdtitle"

251.get_confirm&

{

252.grep-v"

^${cdcatnum},"

$tracks_file>

253.mv$temp_file$tracks_file

254.echo

255.add_record_tracks

256.}

257.fi

258.return

259.}

260.

261.#count_cdsgivesusaquickcountofthecontentsofourdatabase.

262.

263.count_cds（）{

264.set$（wc-l$title_file）

265.num_titles=$1

266.set$（wc-l$tracks_file）

267.num_tracks=$1

268.echofound$num_titlesCDs,withatotalof$num_trackstracks

269.get_return

270.return

271.}

272.

273.#remove_recordsstripsentriesfromthedatabasefiles,usinggrep-vtoremoveall

274.#matchingstrings.Noticewemustuseatemporaryfile.

275.#Ifwetriedtodothis,

276.#grep-v"

^$cdcatnum"

277.#the$title_filewouldbesettoemptybythe>

outputredirectionbeforethegrep

278.#hadchancetoexecute,sogrepwouldreadfromanemptyfile.

279.

280.remove_records（）{

281.if[-z"

282.echoYoumustselectaCDfirst

283.find_cdn

284.fi

285.if[-n"

286.echo"

Youareabouttodelete$cdtitle"

287.get_confirm&

288.grep-v"

289.mv$temp_file$title_file

290.grep-v"

291.mv$temp_file$tracks_file

292.cdcatnum="

293.echoEntryremoved

294.}

295.get_return

296.fi

297.return

298.}

299.

300.#List_tracksagainusesgreptoextractthelineswewant,cuttoaccessthefields

301.

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