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Jose L. Muñoz Juanjo Alins Jorge Mata Oscar Esparza Carlos H. Gañán UPC Telematics Department Linux Networks Contents I Linux Essentials 9 1 Introduction to Unix/Linux 11 2 Introduction to Unix/Linux 13 2.1 Introduction to OS . 13 2.2 Resources Management . 13 2.3 User Interaction . 15 2.4 Implementations and Distros . 16 3 Processes 17 4 Processes 19 4.1 The man command . 19 4.2 Working with the terminal . 19 4.3 Listing processes . 19 4.4 Scripts . 21 4.5 Running in foreground/background . 22 4.6 Signals . 22 4.7 Job Control . 23 4.8 Running multiple commands . 24 4.9 Extra . 25 4.9.1 *Priorities: nice . 25 4.9.2 *Trap: catching signals in scripts . 25 4.9.3 *The terminal and its associated signals . 25 4.9.4 *States of a process . 26 4.9.5 Command Summary . 26 4.10 Practices . 26 5 Filesystem 29 6 Filesystem 31 6.1 Introduction . 31 6.2 Basic types of files . 31 6.3 Hierarchical File Systems . 32 6.4 The path . 33 6.5 Directories . 34 6.6 Files . 35 6.7 File content . 35 6.8 File expansions and quoting . 36 6.9 Links . 36 6.10 Text Files . 37 6.11 Commands and applications for text . 38 6.12 Unix Filesystem permission system . 39 6.12.1 Introduction . 39 6.12.2 Permissions . 39 6.12.3 Change permissions (chmod) . 40 6.12.4 Default permissions . 41 6.13 File System Mounting . 42 6.13.1 Disk usage . 43 6.14 Extra . 44 6.14.1 *inodes . 44 6.14.2 *A file system inside a regular disk file . 45 6.15 Command summary . 46 6.16 Practices . 46 7 File Descriptors 49 8 File Descriptors 51 8.1 File Descriptors . 51 8.2 Redirecting Output . 52 8.3 Redirecting Input . 53 8.4 Unnamed Pipes . 54 8.5 Named Pipes . 55 8.6 Dash . 56 8.7 Process Substitution . 56 8.8 Files in Bash . 57 8.9 Extra . 59 8.9.1 Regular Expressions . 59 8.9.2 tr . 60 8.9.3 find . 61 8.9.4 *xargs . 61 8.10 Command summary . 62 8.11 Practices . 62 II Linux Virtualization 65 9 Introduction to Virtualization 67 10 Introduction to Virtualization 69 10.1 Introduction . 69 10.2 Types of virtualization . 69 10.3 What is UML . 70 10.4 Practical UML . 70 10.5 Update and Install Software in the UML system . 71 10.6 Problems and solutions . 72 10.7 Networking with UML . 72 10.7.1 Virtual switch . 72 10.7.2 Connecting the Host with the UML guests . 73 10.8 Extra . 73 10.8.1 *Building your UML kernel and filesystem . 73 11 Virtual Network UML (VNUML) 77 12 Virtual Network UML (VNUML) 79 12.1 Introduction . 79 12.2 Preliminaries: XML . 79 12.2.1 Introduction . 79 12.2.2 XML Comments . 80 12.2.3 Escaping . 80 12.2.4 Well-formed XML . ..

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