IV The Bash Shell 189
17 Shell Basics 191
17.1 Starting a Shell .. ... . .. . ... . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. 191
17.2 Entering Commands .. .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . .. . . .. . 192
17.3 Working with Files and Directories .. .. . ... . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. 195
17.4 Becoming Root . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . 199
17.5 File Access Permissions ... . .. . . .. . .. . ... . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. 200
17.6 Useful Features of the Shell .. . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . .. 205
17.7 Editing Texts ... . .. . .. . ... . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. . . .. . .. . . .. . .. . . 208
17.8 Searching for Files or Contents .... . . .. . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. . 209
17.9 Viewing Text Files . .. . ... . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . .. 211
17.10 Redirection and Pipes .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . 211
17.11 Starting Programs and Handling Processes . . .. . . .. . .. . ... . .. . ... . .. . .. 213
17.12 Important Linux Commands ... . .. . .. . ... . .. . ... . .. . ... . .. . ... . .. . .. . . .. . 214
18 Bash and Bash Scripts 225
18.1 What is “The Shell”? .. .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. . . 225
18.2 Writing Shell Scripts .... . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . .. 230
18.3 Redirecting Command Events .. .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . . 231
18.4 Using Aliases . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. . . .. . .. . . .. 232
18.5 Using Variables in Bash ... . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . .. . . . 232
18.6 Grouping And Combining Commands ... . .. . ... . .. . .. . . .. . .. . . .. . .. . . .. . . 235
18.7 Working with Common Flow Constructs ... .. . . .. . .. . . .. . .. . ... . .. . ... . .. 235
18.8 For More Information .... . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . . 236
A Help and Troubleshooting 237
A.1 Help and Documentation ... .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . .. . . .. . .. . 237
A.2 Common Problems and Their Solutions .... . .. . ... . .. . ... . .. . .. . . .. . .. . . .. 241
A.3 Legal Notice .. . .. . .. . . .. . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . ... . .. . ... . .. . 269
A.4 GNU Free Documentation License . . .. . . .. . .. . . .. . .. . . .. . .. . ... . .. . ... . .. . . 269
