Busybox Command Descriptions Addgroup Addgroup [-G GID] Group Name [User Name] Adds a Group to the System Options
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At—At, Batch—Execute Commands at a Later Time
at—at, batch—execute commands at a later time at [–csm] [–f script] [–qqueue] time [date] [+ increment] at –l [ job...] at –r job... batch at and batch read commands from standard input to be executed at a later time. at allows you to specify when the commands should be executed, while jobs queued with batch will execute when system load level permits. Executes commands read from stdin or a file at some later time. Unless redirected, the output is mailed to the user. Example A.1 1 at 6:30am Dec 12 < program 2 at noon tomorrow < program 3 at 1945 pm August 9 < program 4 at now + 3 hours < program 5 at 8:30am Jan 4 < program 6 at -r 83883555320.a EXPLANATION 1. At 6:30 in the morning on December 12th, start the job. 2. At noon tomorrow start the job. 3. At 7:45 in the evening on August 9th, start the job. 4. In three hours start the job. 5. At 8:30 in the morning of January 4th, start the job. 6. Removes previously scheduled job 83883555320.a. awk—pattern scanning and processing language awk [ –fprogram–file ] [ –Fc ] [ prog ] [ parameters ] [ filename...] awk scans each input filename for lines that match any of a set of patterns specified in prog. Example A.2 1 awk '{print $1, $2}' file 2 awk '/John/{print $3, $4}' file 3 awk -F: '{print $3}' /etc/passwd 4 date | awk '{print $6}' EXPLANATION 1. Prints the first two fields of file where fields are separated by whitespace. 2. Prints fields 3 and 4 if the pattern John is found. -
Unix Introduction
Unix introduction Mikhail Dozmorov Summer 2018 Mikhail Dozmorov Unix introduction Summer 2018 1 / 37 What is Unix Unix is a family of operating systems and environments that exploits the power of linguistic abstractions to perform tasks Unix is not an acronym; it is a pun on “Multics”. Multics was a large multi-user operating system that was being developed at Bell Labs shortly before Unix was created in the early ’70s. Brian Kernighan is credited with the name. All computational genomics is done in Unix http://www.read.seas.harvard.edu/~kohler/class/aosref/ritchie84evolution.pdfMikhail Dozmorov Unix introduction Summer 2018 2 / 37 History of Unix Initial file system, command interpreter (shell), and process management started by Ken Thompson File system and further development from Dennis Ritchie, as well as Doug McIlroy and Joe Ossanna Vast array of simple, dependable tools that each do one simple task Ken Thompson (sitting) and Dennis Ritchie working together at a PDP-11 Mikhail Dozmorov Unix introduction Summer 2018 3 / 37 Philosophy of Unix Vast array of simple, dependable tools Each do one simple task, and do it really well By combining these tools, one can conduct rather sophisticated analyses The Linux help philosophy: “RTFM” (Read the Fine Manual) Mikhail Dozmorov Unix introduction Summer 2018 4 / 37 Know your Unix Unix users spend a lot of time at the command line In Unix, a word is worth a thousand mouse clicks Mikhail Dozmorov Unix introduction Summer 2018 5 / 37 Unix systems Three common types of laptop/desktop operating systems: Windows, Mac, Linux. Mac and Linux are both Unix-like! What that means for us: Unix-like operating systems are equipped with “shells”" that provide a command line user interface. -
Embedding Redhat Linux in a Diskonchip - HOWTO
Embedding Redhat Linux in a DiskOnChip - HOWTO Don Davies, Prosig Ltd ( [email protected]) October 2002 Describes the configuration and setup of a development environment for a Single Board Computer running Redhat Linux from a DiskOnChip device. Contents 1.0 Introduction ..........................................................................................................3 1.1 Hardware Details..................................................................................................3 1.2 System Configuration ...........................................................................................4 2.0 DOS Development Environment...........................................................................5 2.1 DiskOnChip Tools ................................................................................................5 2.2 Boot Loader..........................................................................................................6 2.3 MS-DOS System Startup......................................................................................6 3.0 Linux Development Environment ......................................................................7 3.1 Custom Kernel Configuration ............................................................................8 3.2 Building Custom Kernel ..................................................................................10 3.3 Booting Custom Kernel ...................................................................................10 3.4 Formatting DiskOnChip for Linux -
Ocaml Standard Library Ocaml V
OCaml Standard Library OCaml v. 3.12.0 | June 7, 2011 | Copyright c 2011 OCamlPro SAS | http://www.ocamlpro.com/ Standard Modules module List module Array Basic Data Types let len = List.length l let t = Array.create len v let t = Array.init len (fun pos -> v_at_pos) Pervasives All basic functions List.iter (fun ele -> ... ) l; let v = t.(pos) String Functions on Strings let l' = List.map(fun ele -> ... ) l t.(pos) <- v; Array Functions on Polymorphic Arrays let l' = List.rev l1 let len = Array.length t List Functions on Polymorphic Lists let acc' = List.fold left (fun acc ele -> ...) acc l let t' = Array.sub t pos len Char Functions on Characters let acc' = List.fold right (fun ele acc -> ...) l acc let t = Array.of_list list Int32 Functions on 32 bits Integers if List.mem ele l then ... let list = Array.to_list t Int64 Functions on 64 bits Integers if List.for all (fun ele -> ele >= 0) l then ... Array.iter (fun v -> ... ) t; Nativeint Functions on Native Integers if List.exists (fun ele -> ele < 0) l then ... let neg = List.find (fun x -> x < 0) ints Array.iteri (fun pos v -> ... ) t; Advanced Data Types let negs = List.find all (fun x -> x < 0) ints let t' = Array.map (fun v -> ... ) t let t' = Array.mapi (fun pos v -> ... ) t Buffer Automatically resizable strings let (negs,pos) = List.partition (fun x -> x < 0) ints let ele = List.nth 2 list let concat = Array.append prefix suffix Complex Complex Numbers Array.sort compare t; Digest MD5 Checksums let head = List.hd list Hashtbl Polymorphic Hash Tables let tail = List.tl list let value = List.assoc key assocs Queue Polymorphic FIFO module Char Stack Polymorphic LIFO if List.mem assoc key assocs then .. -
CNTR: Lightweight OS Containers
CNTR: Lightweight OS Containers Jorg¨ Thalheim, Pramod Bhatotia Pedro Fonseca Baris Kasikci University of Edinburgh University of Washington University of Michigan Abstract fundamental to achieve high efficiency in virtualized datacenters and enables important use-cases, namely Container-based virtualization has become the de-facto just-in-time deployment of applications. Moreover, standard for deploying applications in data centers. containers significantly reduce operational costs through However, deployed containers frequently include a higher consolidation density and power minimization, wide-range of tools (e.g., debuggers) that are not required especially in multi-tenant environments. Because of all for applications in the common use-case, but they these advantages, it is no surprise that containers have seen are included for rare occasions such as in-production wide-spread adoption by industry, in many cases replacing debugging. As a consequence, containers are significantly altogether traditional virtualization solutions [17]. larger than necessary for the common case, thus increasing the build and deployment time. Despite being lightweight, deployed containers often include a wide-range of tools such as shells, editors, CNTR1 provides the performance benefits of lightweight coreutils, and package managers. These additional tools containers and the functionality of large containers by are usually not required for the application’s core function splitting the traditional container image into two parts: the — the common operational use-case — but they are “fat” image — containing the tools, and the “slim” image included for management, manual inspection, profiling, — containing the main application. At run-time, CNTR and debugging purposes [64]. In practice, this significantly allows the user to efficiently deploy the “slim” image and increases container size and, in turn, translates into then expand it with additional tools, when and if necessary, slower container deployment and inefficient datacenter by dynamically attaching the “fat” image. -
Version 7.8-Systemd
Linux From Scratch Version 7.8-systemd Created by Gerard Beekmans Edited by Douglas R. Reno Linux From Scratch: Version 7.8-systemd by Created by Gerard Beekmans and Edited by Douglas R. Reno Copyright © 1999-2015 Gerard Beekmans Copyright © 1999-2015, Gerard Beekmans All rights reserved. This book is licensed under a Creative Commons License. Computer instructions may be extracted from the book under the MIT License. Linux® is a registered trademark of Linus Torvalds. Linux From Scratch - Version 7.8-systemd Table of Contents Preface .......................................................................................................................................................................... vii i. Foreword ............................................................................................................................................................. vii ii. Audience ............................................................................................................................................................ vii iii. LFS Target Architectures ................................................................................................................................ viii iv. LFS and Standards ............................................................................................................................................ ix v. Rationale for Packages in the Book .................................................................................................................... x vi. Prerequisites -
Reference Guide
Reference Guide Scyld ClusterWare Release 5.10.1-5101g0000 December 18, 2013 Reference Guide: Scyld ClusterWare Release 5.10.1-5101g0000; December 18, 2013 Revised Edition Published December 18, 2013 Copyright © 1999 - 2013 Penguin Computing, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of Penguin Computing, Inc.. The software described in this document is "commercial computer software" provided with restricted rights (except as to included open/free source). Use beyond license provisions is a violation of worldwide intellectual property laws, treaties, and conventions. Scyld ClusterWare, the Highly Scyld logo, and the Penguin Computing logo are trademarks of Penguin Computing, Inc.. Intel is a registered trademark of Intel Corporation or its subsidiaries in the United States and other countries. Infiniband is a trademark of the InfiniBand Trade Association. Linux is a registered trademark of Linus Torvalds. Red Hat and all Red Hat-based trademarks are trademarks or registered trademarks of Red Hat, Inc. in the United States and other countries. All other trademarks and copyrights referred to are the property of their respective owners. Table of Contents Preface .....................................................................................................................................................................................v -
A Multiplatform Pseudo Terminal
A Multi-Platform Pseudo Terminal API Project Report Submitted in Partial Fulfillment for the Masters' Degree in Computer Science By Qutaiba Mahmoud Supervised By Dr. Clinton Jeffery ABSTRACT This project is the construction of a pseudo-terminal API, which will provide a pseudo-terminal interface access to interactive programs. The API is aimed at developing an extension to the Unicon language to allow Unicon programs to easily utilize applications that require user interaction via a terminal. A pseudo-terminal is a pair of virtual devices that provide a bidirectional communication channel. This project was constructed to enable an enhancement to a collaborative virtual environment, because it will allow external tools such to be utilized within the same environment. In general the purpose of this API is to allow the UNICON runtime system to act as the user via the terminal which is provided by the API, the terminal is in turn connected to a client process such as a compiler, debugger, or an editor. It can also be viewed as a way for the UNICON environment to control and customize the input and output of external programs. Table of Contents: 1. Introduction 1.1 Pseudo Terminals 1.2 Other Terminals 1.3 Relation To Other Pseudo Terminal Applications. 2. Methodology 2.1 Pseudo Terminal API Function Description 3. Results 3.1 UNIX Implementation 3.2 Windows Implementation 4. Conclusion 5. Recommendations 6. References Acknowledgments I would like to thank my advisor, Dr. Clinton Jeffery, for his support, patience and understanding. Dr. Jeffery has always been prompt in delivering and sharing his knowledge and in providing his assistance. -
Securing Embedded Systems: Analyses of Modern Automotive Systems and Enabling Near-Real Time Dynamic Analysis
Securing Embedded Systems: Analyses of Modern Automotive Systems and Enabling Near-Real Time Dynamic Analysis Karl Koscher A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Washington 2014 Reading Committee: Tadayoshi Kohno, Chair Gaetano Borriello Shwetak Patel Program Authorized to Offer Degree: Computer Science and Engineering © Copyright 2014 Karl Koscher University of Washington Abstract Securing Embedded Systems: From Analyses of Modern Automotive Systems to Enabling Dynamic Analysis Karl Koscher Chair of the Supervisory Committee: Associate Professor Tadayoshi Kohno Department of Computer Science and Engineering Today, our life is pervaded by computer systems embedded inside everyday products. These embedded systems are found in everything from cars to microwave ovens. These systems are becoming increasingly sophisticated and interconnected, both to each other and to the Internet. Unfortunately, it appears that the security implications of this complexity and connectivity have mostly been overlooked, even though ignoring security could have disastrous consequences; since embedded systems control much of our environment, compromised systems could be used to inflict physical harm. This work presents an analysis of security issues in embedded systems, including a comprehensive security analysis of modern automotive systems. We hypothesize that dynamic analysis tools would quickly discover many of the vulnerabilities we found. However, as we will discuss, there -
High Performance Multi-Node File Copies and Checksums for Clustered File Systems∗
High Performance Multi-Node File Copies and Checksums for Clustered File Systems∗ Paul Z. Kolano, Robert B. Ciotti NASA Advanced Supercomputing Division NASA Ames Research Center, M/S 258-6 Moffett Field, CA 94035 U.S.A. {paul.kolano,bob.ciotti}@nasa.gov Abstract To achieve peak performance from such systems, it is Mcp and msum are drop-in replacements for the stan- typically necessary to utilize multiple concurrent read- dard cp and md5sum programs that utilize multiple types ers/writers from multiple systems to overcome various of parallelism and other optimizations to achieve maxi- single-system limitations such as number of processors mum copy and checksum performance on clustered file and network bandwidth. The standard cp and md5sum systems. Multi-threading is used to ensure that nodes are tools of GNU coreutils [11] found on every modern kept as busy as possible. Read/write parallelism allows Unix/Linux system, however, utilize a single execution individual operations of a single copy to be overlapped thread on a single CPU core of a single system, hence using asynchronous I/O. Multi-node cooperation allows cannot take full advantage of the increased performance different nodes to take part in the same copy/checksum. of clustered file system. Split file processing allows multiple threads to operate This paper describes mcp and msum, which are drop- concurrently on the same file. Finally, hash trees allow in replacements for cp and md5sum that utilize multi- inherently serial checksums to be performed in parallel. ple types of parallelism to achieve maximum copy and This paper presents the design of mcp and msum and de- checksum performance on clustered file systems. -
Praat Scripting Tutorial
Praat Scripting Tutorial Eleanor Chodroff Newcastle University July 2019 Praat Acoustic analysis program Best known for its ability to: Visualize, label, and segment audio files Perform spectral and temporal analyses Synthesize and manipulate speech Praat Scripting Praat: not only a program, but also a language Why do I want to know Praat the language? AUTOMATE ALL THE THINGS Praat Scripting Why can’t I just modify others’ scripts? Honestly: power, flexibility, control Insert: all the gifs of ‘you can do it’ and ‘you got this’ and thumbs up Praat Scripting Goals ~*~Script first for yourself, then for others~*~ • Write Praat scripts quickly, effectively, and “from scratch” • Learn syntax and structure of the language • Handle various input/output combinations Tutorial Overview 1) Praat: Big Picture 2) Getting started 3) Basic syntax 4) Script types + Practice • Wav files • Measurements • TextGrids • Other? Praat: Big Picture 1) Similar to other languages you may (or may not) have used before • String and numeric variables • For-loops, if else statements, while loops • Regular expression matching • Interpreted language (not compiled) Praat: Big Picture 2) Almost everything is a mouse click! i.e., Praat is a GUI scripting language GUI = Graphical User Interface, i.e., the Objects window If you ever get lost while writing a Praat script, click through the steps using the GUI Getting Started Open a Praat script From the toolbar, select Praat à New Praat script Save immediately! Save frequently! Script Goals and Input/Output • Consider what -
Chapter 1 Introducing Python
3 Chapter 1 Introducing Python 1.1: Introduction Python is a programming language that is both simple and powerful. For those who have struggled with learning programming languages in the past, this may come as a pleasant surprise. This chapter describes some of the main features of Python and its use as a programming language to write scripts for ArcGIS. The logic and struc- ture of this book and the accompanying exercises is described, followed by some examples of how Python is used. The final part of this chapter intro- duces Python editors that make it easier to write and organize your code. 1.2: Exploring the features of Python Python has a number of features that make it the programming language of choice for working with ArcGIS. Among them: It’s simple and easy to learn: Python is easy to learn compared with other highly structured programming languages like C++ or Visual Basic. The syntax is simple, which gives you more time to focus on solving problems than having to learn the language itself. It’s free and open source: Python is free and open source software ( FOSS ). You can freely distribute copies of the software, read the source code, make changes to it, and use pieces of it in new free programs. One of the reasons Python works so well is that it has been created, and is constantly being improved, by an active and dedicated user community. The FOSS nature of Python makes it possible for Esri to distribute Python with ArcGIS software. It’s cross platform: Python is supported on different platforms, includ- ing Windows, Mac, Linux, and many others.