~ubuntu-branches/ubuntu/precise/kubuntu-docs/precise-proposed

>This document provides a brief description of the Linux command line. It is not a complete guide to the command line, but rather an introduction to complement &kubuntu;'s graphical tools. </para>

</abstract>

</articleinfo>

<title

>Úvod</title>

<para>

<emphasis

>"Under Linux there are GUIs (graphical user interfaces), where you can point and click and drag, and hopefully get work done without first reading lots of documentation. The traditional Unix environment is a CLI (command line interface), where you type commands to tell the computer what to do. That is faster and more powerful, but requires finding out what the commands are." -- from <emphasis role="strong"

>man intro(1)</emphasis

> </emphasis>

</para>

<para

>This guide describes some basic GNU/Linux shell commands. It is not intended to be a complete guide to the command line, just an introduction to complement &kubuntu;'s graphical tools. </para>

<para>

<para

>Všechny názvy příkazů, souborů nebo cesty k adresářům jsou zobrazeny použitím <command

>neproporcionálního písma</command

>. </para>

</listitem>

<para

>The commands should be issued from a command prompt within a <application

>Terminal</application

> and will be shown as: <screen

>command to type</screen>

</para>

</listitem>

<para

><emphasis role="strong"

>Command Line Linux is case sensitive.</emphasis

> User, user, and USER are each different and distinct in Linux. </para>

</listitem>

</itemizedlist>

</para>

</sect1>

<title

>Starting A Terminal</title>

<para

>&kubuntu;'s Terminal application is called <application

>Konsole</application

>, and is opened by going to &menukonsole;. </para>

<para>

<title

>&kubuntu;'s terminal - Konsole</title>

</imageobject>

</mediaobject>

</example>

</para>

</sect1>

<title

>File and Directory Commands</title>

<title

>pwd - print working directory</title>

<para

>The <command

>pwd</command

> command displays the directory where the user is currently located. (<acronym

>pwd</acronym

> stands for <quote

>print working directory</quote

>). For example, typing <screen

>pwd</screen

> while in the <filename class="directory"

>Desktop</filename

> will show <computeroutput

>/home/[username]/Desktop</computeroutput

>. <note

100

> <para

101

><application

102

>Konsole</application

103

> also displays this information in both the tab and title bar of its window. </para>

104

</note>

105

</para>

106

</sect2>

107

108

<title

109

>cd - change directory</title>

110

<para

111

>The <command

112

>cd</command

113

> command changes directories. (<acronym

114

>cd</acronym

115

> stands for <quote

116

>change directory</quote

117

>). When a terminal window is opened, it will be in the user's home directory. Moving around the file system requires the use of the <command

118

>cd</command

119

>. </para>

120

121

122

<para

123

>To navigate into the root directory, type: <screen

124

>cd /</screen>

125

</para>

126

</listitem>

127

128

<para

129

>To navigate to the current user's home directory, type: <screen

130

>cd</screen

131

> or <screen

132

>cd ~</screen>

133

</para>

134

<note>

135

<para

136

>The <command

137

>~</command

138

> character represents the current user's home directory. As shown above, <command

139

>cd ~</command

140

> is equivalent to <command

141

>cd /home/username/</command

142

>. However, when running a command as root (using <command

143

>sudo</command

144

>, for example), <command

145

>~</command

146

> points to <filename class="directory"

147

>/root</filename

148

>. When running a <command

149

>cd</command

150

> command with <command

151

>sudo</command

152

>, the full path to the home directory must be given. </para>

153

</note>

154

</listitem>

155

156

<para

157

>To navigate up one directory level, type: <screen

158

>cd ..</screen>

159

</para>

160

</listitem>

161

162

<para

163

>To navigate up two directory levels, type: <screen

164

>cd ../../</screen>

165

</para>

166

</listitem>

167

168

<para

169

>To navigate to the previous directory (go back), type: <screen

170

>cd -</screen>

171

</para>

172

</listitem>

173

174

<para

175

>To navigate through multiple levels of directories at once, specify the full directory path. For example, type: <screen

176

>cd /var/log</screen

177

> to go directly to the <filename class="directory"

178

>/log</filename

179

> subdirectory of <filename class="directory"

180

>/var/</filename

181

>. For another example, typing: <screen

182

>cd ~/Desktop</screen

183

> moves to the <filename class="directory"

184

>Desktop</filename

185

> subdirectory inside the current user's home directory. </para>

186

</listitem>

187

</itemizedlist>

188

</sect2>

189

190

<title

191

>ls - list files</title>

192

<para

193

>The <command

194

>ls</command

195

> command outputs a list of the files in the current directory. (<acronym

196

>ls</acronym

197

> is short for <quote

198

>list</quote

199

>). For example, typing <screen

200

>ls ~</screen

201

> will display the files that are in the current user's home directory. </para>

202

<para

203

>Used with the <command

204

>-l</command

205

> option, <command

206

>ls</command

207

> outputs other information along with the filename, such as the permissions on the file, the file's owner, and more. </para>

208

<para

209

>Used with the <command

210

>-al</command

211

> options, <command

212

>ls</command

213

> outputs the information associated with the <command

214

>-l</command

215

> option in addition to showing hidden files (<command

216

>a</command

217

> option). </para>

218

</sect2>

219

220

<title

221

>touch - create empty file</title>

222

<para

223

>The <command

224

>touch</command

225

> command is used either to change a file's access and modification timestamps or to create a new empty file. For example, <screen

226

>touch foo</screen

227

> will create a new empty file named <filename

228

>foo</filename

229

>. If <filename

230

>foo</filename

231

> is already a file, then using <command

232

>touch</command

233

> will update the timestamps on the file which will show the last time a file was <emphasis

234

>touched</emphasis

235

>. </para>

236

</sect2>

237

238

<title

239

>mkdir - make directory</title>

240

<para

241

>The <command

242

>mkdir</command

243

> command is used to create a new directory. (<acronym

244

>mkdir</acronym

245

> stands for <quote

246

>make directory</quote

247

>). To create a new directory named <filename class="directory"

248

>foobar</filename

249

>, type: <screen

250

>mkdir foobar</screen>

251

</para>

252

</sect2>

253

254

<title

255

>cp - copy files or directories</title>

256

<para

257

>The <command

258

>cp</command

259

> command makes a copy of a file or directory. (<acronym

260

>cp</acronym

261

> is short for <quote

262

>copy</quote

263

>). To make an exact copy of <filename

264

>foo</filename

265

> and name it <filename

266

>bar</filename

267

>, type: <screen

268

>cp foo bar</screen

269

> To make an exact copy of the <filename class="directory"

270

>foo_dir</filename

271

> directory and name it <filename class="directory"

272

>bar_dir</filename

273

>, type: <screen

274

>cp -r foo_dir bar_dir</screen>

275

</para>

276

</sect2>

277

278

<title

279

>mv - move files or directories</title>

280

<para

281

>The <command

282

>mv</command

283

> command moves a file or directory to a different location or will rename a file or directory. (<acronym

284

>mv</acronym

285

> is short for <quote

286

>move</quote

287

>). To rename the file <filename

288

>foo</filename

289

> to <filename

290

>bar</filename

291

>, type: <screen

292

>mv foo bar</screen

293

> To move the file <filename

294

>foo</filename

295

> into the current user's <filename class="directory"

296

>Desktop</filename

297

> directory, type: <screen

298

>mv foo ~/Desktop</screen

299

> This will not rename <filename

300

>foo</filename

301

> to <filename

302

>Desktop</filename

303

> because <filename

304

>foo</filename

305

> is a file and <filename class="directory"

306

>Desktop</filename

307

> is a directory. </para>

308

</sect2>

309

310

<title

311

>rm - remove files or directories</title>

312

<para

313

>The <command

314

>rm</command

315

> command is used to delete files and directories. (<acronym

316

>rm</acronym

317

> is short for <quote

318

>remove</quote

319

>). To delete the file <filename

320

>foo</filename

321

> for the current directory, type: <screen

322

>rm foo</screen>

323

</para>

324

<para

325

>By default, <command

326

>rm</command

327

> will not remove directories. To remove a directory, you must use the <command

328

>-r</command

329

> option (also can be entered as either <command

330

>-R</command

331

> or <command

332

>--recursive</command

333

>). For example, <screen

334

>rm -r foobar</screen

335

> or <screen

336

>rm -R foobar</screen

337

> or <screen

338

>rm --recursive foobar</screen

339

> will remove the directory <filename class="directory"

340

>foobar</filename

341

>, <emphasis role="strong"

342

> and all of its contents!</emphasis

343

> </para>

344

</sect2>

345

346

</sect1>

347

348

349

350

<title

351

>System Information Commands</title>

352

353

<title

354

>df - display amount of disk space</title>

355

<para

356

>The <command

357

>df</command

358

> command displays filesystem disk space usage for all partitions. (<acronym

359

>df</acronym

360

> stands for <quote

361

>disk free</quote

362

>). <screen

363

>df -h</screen

364

> will give information using megabytes (<abbrev

365

>M</abbrev

366

>) and gigabytes (<abbrev

367

>G</abbrev

368

>) instead of blocks (<command

369

>-h</command

370

> means <quote

371

>human readable</quote

372

>). </para>

373

</sect2>

374

375

<title

376

>free - display amount of free and used memory</title>

377

<para

378

>The <command

379

>free</command

380

> command displays the amount of free and used memory in the system. <screen

381

>free -m</screen

382

> will give the information using megabytes, which is probably the most useful for current computers. </para>

383

</sect2>

384

385

<title

386

>top - display top consuming processes</title>

387

<para

388

>The <command

389

>top</command

390

> command displays information on the Linux system - processes that are running, system resources including <acronym

391

>CPU</acronym

392

>, <acronym

393

>RAM</acronym

394

> & swap usage, and the total number of tasks being run. To exit <command

395

>top</command

396

>, press <keycap

397

>q</keycap

398

>. </para>

399

</sect2>

400

401

<title

402

>uname - print details about the current machine</title>

403

<para

404

>The <command

405

>uname</command

406

> command with the <command

407

>-a</command

408

> options displays all system information, including machine name, kernel name & version, and other details. This command is useful for checking which kernel is in use. (<abbrev

409

>uname</abbrev

410

> is short for <quote

411

>unix name</quote

412

>). </para>

413

</sect2>

414

415

<title

416

>lsb_release - print details about current Linux release</title>

417

<para

418

>The <command

419

>lsb_release</command

420

> with the <command

421

>-a</command

422

> option prints version information for the Linux release in use. For example, typing: <screen

423

>lsb_release -a</screen

424

> will display: <screen

425

>No LSB modules are available.

426

Distributor ID: Ubuntu

427

Description: Ubuntu &distro-rev;

428

Release: &distro-rev;

429

Codename: &distro-short-codename;

430

</screen>

431

</para>

432

</sect2>

433

</sect1>

434

435

436

437

<title

438

>Executing Commands with Elevated Privileges</title>

439

<para

440

>The following commands must be prefaced with the <command

441

>sudo</command

442

> command. Please see <ulink url="https://help.ubuntu.com/community/RootSudo"

443

>RootSudo</ulink

444

> for information on using <command

445

>sudo</command

446

>. (<abbrev

447

>sudo</abbrev

448

> is short for <quote

449

>superuser do</quote

450

>). </para>

451

452

<title

453

>Adding a New Group</title>

454

<para

455

>The <command

456

>addgroup</command

457

> command is used to create a new group in the system. To create a new group, type: <screen

458

>sudo addgroup foobar</screen

459

> The above command will create a new group called <emphasis role="strong"

460

>foobar</emphasis

461

>. </para>

462

</sect2>

463

464

<title

465

>Adding a New User</title>

466

<para

467

>The <command

468

>adduser</command

469

> command is used to create a new user on the system. To create a new user, type: <screen

470

>adduser foobar</screen

471

> which will create a new user called <emphasis role="strong"

472

>foobar</emphasis

473

>. </para>

474

</sect2>

475

476

<title

477

>Add or Change a User Password</title>

478

<para

479

>The <command

480

>passwd</command

481

> command is used to assign a new password to a new user or to change the current password for an existing user. To add a password or change the password for the user <emphasis role="strong"

482

>foobar</emphasis

483

>, type: <screen

484

>passwd foobar</screen

485

> For new users, this will generate a prompt to enter the new password. For an existing user, there will be a prompt for the existing password before the prompt for a new password. </para>

486

</sect2>

487

488

<title

489

>Assign User to Group</title>

490

<para

491

>To assign the user <emphasis role="strong"

492

>foobar</emphasis

493

> to the group <emphasis role="strong"

494

>barfoo</emphasis

495

>, type: <screen

496

>adduser foobar barfoo</screen>

497

</para>

498

</sect2>

499

</sect1>

500

501

502

503

<title

504

>Options</title>

505

<para

506

>The default behavior for a command may usually be modified by adding <command

507

>--option</command

508

> to the command. For example, the <link linkend="ls"

509

><command

510

>ls</command

511

></link

512

> command has an <command

513

>-s</command

514

> option. The <command

515

>ls -s</command

516

> will include file sizes in the listing. There is also a <command

517

>-h</command

518

> option to display file sizes in a <quote

519

>human readable</quote

520

> format. </para>

521

<para

522

>Options can be grouped in clusters, so <screen

523

>ls -sh</screen

524

> is the same command as <screen

525

> ls -s -h</screen

526

> Most options have a long version, prefixed with two dashes instead of one, so <screen

527

>ls --size --human-readable</screen

528

> is also the same command as <screen

529

>ls -sh</screen>

530

</para>

531

</sect1>

532

533

534

535

<title

536

><quote

537

>Man</quote

538

> and Getting Help</title>

539

<para

540

><emphasis role="strong"

541

><emphasis

542

>command</emphasis

543

> --help</emphasis

544

> and <command

545

>man</command

546

> <emphasis role="strong"

547

><emphasis

548

>command</emphasis

549

></emphasis

550

> are the two most important tools at the command line. </para>

551

<para

552

>Virtually all commands understand the <command

553

>-h</command

554

> (or <command

555

>--help</command

556

>) option which will produce a short usage description of the command and its options, then exit back to the command prompt. Type: <screen

557

>man -h</screen

558

> or <screen

559

>man --help</screen

560

> to see this in action. </para>

561

<para

562

>Every command and nearly every application in Linux has a <abbrev

563

>man</abbrev

564

> (manual) file. It is as simple as typing <command

565

>man command</command

566

> to bring up a longer manual entry for the specified command. For example: <screen

567

>man mv</screen

568

> brings up the <command

569

>mv</command

570

> manual. </para>

571

<para

572

>Move up and down the man file with the arrow keys, and quit back to the command prompt with <keycap

573

>q</keycap

574

>. </para>

575

<para>

576

<screen

577

>man man</screen>

578

brings up the manual entry for the <command

579

>man</command

580

> command, which is a good place to start. </para>

581

<para>

582

<screen

583

>man intro</screen>

584

is especially useful. It displays the <quote

585

>introduction to user commands</quote

586

> which is a well-written, brief introduction to the Linux command line. </para>

587

<para

588

>There are also <command

589

>info</command

590

> pages, which generally go into more detail than <command

591

>man</command

592

> pages. Try: <screen

593

>info info</screen

594

> for the introduction to info pages. </para>

595

596

<title

597

>Searching for man files</title>

598

<para

599

>If you aren't sure which command or application you need to use, you can search the <command

600

>man</command

601

> files. </para>

602

<para

603

>To search the <command

604

>man</command

605

> files for <command

606

>konsole</command

607

>, try: <screen

608

>man -k konsole</screen>

609

</para>

610

<note>

611

<para

612

>This is the same as the <command

613

>apropos</command

614

> command. </para>

615

</note>

616

<para

617

>To search only the titles of your system's <command

618

>man</command

619

> files, try: <screen

620

>man -f kde</screen>

621

</para>

622

<note>

623

<para

624

>This is the same as the <command

625

>whatis</command

626

> command. </para>

627

</note>

628

</sect2>

629

</sect1>

630

631

632

633

<title

634

>Cutting and Pasting</title>

635

<para

636

>There are often situations that require text to be pasted into the terminal. </para>

637

<para

638

>Text copied from a web page using <keycombo

639

><keycap

640

>Ctrl</keycap

641

><keycap

642

>C</keycap

643

></keycombo

644

> won't paste with <keycombo

645

><keycap

646

>Ctrl</keycap

647

><keycap

648

>V</keycap

649

></keycombo

650

> as it does in other applications because the terminal uses a different combination for paste, <keycombo

651

><keycap

652

>Shift</keycap

653

><keycap

654

>Insert</keycap

655

></keycombo

656

>. Pasting can also be done using the mouse by <mousebutton

657

>right-clicking</mousebutton

658

> in the terminal and selecting <guimenuitem

659

>Paste</guimenuitem

660

> from the menu. </para>

661

<para

662

>Text can also be copied by selecting (highlighting) the text to be copied. Clicking the <mousebutton

663

>middle</mousebutton

664

> button on the mouse (or both buttons simultaneously on a two-button mouse) in the terminal pastes the selected text. </para>

665

<note>

666

<para

667

>These actions may work differently in other terminal emulators than <application

668

>Konsole</application

669

>. Consult your terminal emulator's documentation for details. </para>

670

</note>

671

</sect1>

672

673

674

675

<title

676

>Tips</title>

677

<variablelist

678

><title

679

>Save on Typing</title>

680

681

<term

682

><keycap

683

>Up Arrow</keycap

684

> or <keycombo

685

><keycap

686

>Ctrl</keycap

687

><keycap

688

>p</keycap

689

></keycombo

690

> </term>

691

692

<para

693

>Scrolls backwards through the commands entered previously </para>

694

</listitem>

695

</varlistentry>

696

697

<term

698

><keycap

699

>Down Arrow</keycap

700

> or <keycombo

701

><keycap

702

>Ctrl</keycap

703

><keycap

704

>n</keycap

705

></keycombo

706

> </term>

707

708

<para

709

>Scrolls forward through previous commands </para>

710

</listitem>

711

</varlistentry>

712

713

<term>

714

<keycap

715

>Enter</keycap>

716

</term>

717

718

<para

719

>Executes the command selected </para>

720

</listitem>

721

</varlistentry>

722

723

<term>

724

<keycap

725

>Tab</keycap>

726

</term>

727

728

<para

729

>Tab is a useful feature. It autocompletes any commands or filenames if there is one option, otherwise it displays a list of options that fit the information entered. Using tab in this way reduces typing errors. </para>

730

</listitem>

731

</varlistentry>

732

</variablelist>

733

734

<variablelist

735

><title

736

>Change the Text</title>

737

<note>

738

<para

739

>The mouse won't work to position the cursor in a command line entry. Use the <keycap

740

>Left Arrow</keycap

741

> or the <keycap

742

>Right Arrow</keycap

743

> keys to move within the line. </para>

744

</note>

745

<note>

746

<para

747

>Typing at the cursor <emphasis

748

>inserts</emphasis

749

> text there. It doesn't overwrite what is already there. </para>

750

</note>

751

752

<term

753

><keycombo

754

><keycap

755

>Ctrl</keycap

756

><keycap

757

>a</keycap

758

></keycombo

759

> or <keycap

760

>Home</keycap

761

> </term>

762

763

<para

764

>Moves the cursor to the <emphasis

765

>start</emphasis

766

> of the line </para>

767

</listitem>

768

</varlistentry>

769

770

<term

771

><keycombo

772

><keycap

773

>Ctrl</keycap

774

><keycap

775

>e</keycap

776

></keycombo

777

> or <keycap

778

>End</keycap

779

> </term>

780

781

<para

782

>Moves the cursor to the <emphasis

783

>end</emphasis

784

> of the line </para>

785

</listitem>

786

</varlistentry>

787

788

<term>

789

<keycombo

790

><keycap

791

>Ctrl</keycap

792

><keycap

793

>k</keycap

794

></keycombo>

795

</term>

796

797

<para

798

>Deletes from the current cursor position to the end of the line </para>

799

</listitem>

800

</varlistentry>

801

802

<term>

803

<keycombo

804

><keycap

805

>Ctrl</keycap

806

><keycap

807

>u</keycap

808

></keycombo>

809

</term>

810

811

<para

812

>Deletes the entire current line </para>

813

</listitem>

814

</varlistentry>

815

816

<term>

817

<keycombo

818

><keycap

819

>Ctrl</keycap

820

><keycap

821

>w</keycap

822

></keycombo>

823

</term>

824

825

<para

826

>Deletes the word before the cursor </para>

827

</listitem>

828

</varlistentry>

829

</variablelist>

830

</sect1>

831

832

833

834

<title

835

>More Information</title>

836

<para

837

>The following online guides are available: </para>

838

839

840

<para

841

><ulink url="https://help.ubuntu.com/community/AptGetHowto"

842

>AptGetHowto</ulink

843

> - using <command

844

>apt-get</command

845

> to install packages from the command line. </para>

846

</listitem>

847

848

<para

849

><ulink url="https://help.ubuntu.com/community/Repositories/CommandLine"

850

>Commandline Repository Editing</ulink

851

> - managing software repositories through the command line. </para>

852

</listitem>

853

854

<para

855

><ulink url="https://help.ubuntu.com/community/grep"

856

><command

857

>grep</command

858

> Howto</ulink

859

> - <command

860

>grep</command

861

> is a powerful command line search tool. </para>

862

</listitem>

863

864

<para

865

><ulink url="https://help.ubuntu.com/community/find"

866

><command

867

>find</command

868

></ulink

869

> - locate files from the command line. </para>

870

</listitem>

871

872

<para

873

><ulink url="https://help.ubuntu.com/community/CommandlineHowto"

874

>Commandline Howto</ulink

875

> - longer and more complete than this basic guide; still not finished however. </para>

876

</listitem>

877

878

<para

879

><ulink url="https://help.ubuntu.com/community/HowToReadline"

880

>Howto Readline</ulink

881

> - information on more advanced customization for the command line. </para>

882

</listitem>

883

</itemizedlist>

884

<para

885

>For more detailed tutorials on the Linux command line, please see: </para>

886

887

888

<para

889

><ulink url="http://ss64.com/bash/"

890

></ulink

891

> - an A-Z index of the Bash command line for Linux. </para>

892

</listitem>

893

894

<para

895

><ulink url="http://linuxcommand.org/"

896

></ulink

897

> - basic <acronym

898

>BASH</acronym

899

> tutorials, including <acronym

900

>BASH</acronym

901

> scripting. </para>

902

</listitem>

903

904

<para

905

><ulink url="http://linuxsurvival.com/index.php"

906

></ulink

907

> - Java-based tutorials. </para>

908

</listitem>

909

910

<para

911

><ulink url="http://rute.2038bug.com/index.html.gz"

912

></ulink

913

> - a massive online book about system administration, almost all from the command line. </para>

914

</listitem>

915

916

<para

917

><ulink url="http://www.commandlinefu.com/"

918

></ulink

919

> - a place to record command-line favorites and view other's gems as well. </para>

920

</listitem>

921

</itemizedlist>

922

</sect1>

923

924

</article>

925

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