Cron Job, Crontab -E, -L Using
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
Oracle® Linux 7 Monitoring and Tuning the System
Oracle® Linux 7 Monitoring and Tuning the System F32306-03 October 2020 Oracle Legal Notices Copyright © 2020, Oracle and/or its affiliates. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, then the following notice is applicable: U.S. GOVERNMENT END USERS: Oracle programs (including any operating system, integrated software, any programs embedded, installed or activated on delivered hardware, and modifications of such programs) and Oracle computer documentation or other Oracle data delivered to or accessed by U.S. Government end users are "commercial computer software" or "commercial computer software documentation" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, reproduction, duplication, release, display, disclosure, modification, preparation of derivative works, and/or adaptation of i) Oracle programs (including any operating system, integrated software, any programs embedded, installed or activated on delivered hardware, and modifications of such programs), ii) Oracle computer documentation and/or iii) other Oracle data, is subject to the rights and limitations specified in the license contained in the applicable contract. -
The /Proc File System
09 0430 CH07 5/22/01 10:30 AM Page 147 7 The /proc File System TRY INVOKING THE mount COMMAND WITHOUT ARGUMENTS—this displays the file systems currently mounted on your GNU/Linux computer.You’ll see one line that looks like this: none on /proc type proc (rw) This is the special /proc file system. Notice that the first field, none, indicates that this file system isn’t associated with a hardware device such as a disk drive. Instead, /proc is a window into the running Linux kernel. Files in the /proc file system don’t corre- spond to actual files on a physical device. Instead, they are magic objects that behave like files but provide access to parameters, data structures, and statistics in the kernel. The “contents” of these files are not always fixed blocks of data, as ordinary file con- tents are. Instead, they are generated on the fly by the Linux kernel when you read from the file.You can also change the configuration of the running kernel by writing to certain files in the /proc file system. Let’s look at an example: % ls -l /proc/version -r--r--r-- 1 root root 0 Jan 17 18:09 /proc/version Note that the file size is zero; because the file’s contents are generated by the kernel, the concept of file size is not applicable.Also, if you try this command yourself, you’ll notice that the modification time on the file is the current time. 09 0430 CH07 5/22/01 10:30 AM Page 148 148 Chapter 7 The /proc File System What’s in this file? The contents of /proc/version consist of a string describing the Linux kernel version number. -
A.5.1. Linux Programming and the GNU Toolchain
Making the Transition to Linux A Guide to the Linux Command Line Interface for Students Joshua Glatt Making the Transition to Linux: A Guide to the Linux Command Line Interface for Students Joshua Glatt Copyright © 2008 Joshua Glatt Revision History Revision 1.31 14 Sept 2008 jg Various small but useful changes, preparing to revise section on vi Revision 1.30 10 Sept 2008 jg Revised further reading and suggestions, other revisions Revision 1.20 27 Aug 2008 jg Revised first chapter, other revisions Revision 1.10 20 Aug 2008 jg First major revision Revision 1.00 11 Aug 2008 jg First official release (w00t) Revision 0.95 06 Aug 2008 jg Second beta release Revision 0.90 01 Aug 2008 jg First beta release License This document is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License [http:// creativecommons.org/licenses/by-nc-sa/3.0/us/]. Legal Notice This document is distributed in the hope that it will be useful, but it is provided “as is” without express or implied warranty of any kind; without even the implied warranties of merchantability or fitness for a particular purpose. Although the author makes every effort to make this document as complete and as accurate as possible, the author assumes no responsibility for errors or omissions, nor does the author assume any liability whatsoever for incidental or consequential damages in connection with or arising out of the use of the information contained in this document. The author provides links to external websites for informational purposes only and is not responsible for the content of those websites. -
Regular Expressions and Sed &
Regular expressions and sed & awk Regular expressions • Key to powerful, efficient, and flexible text processing by allowing for variable information in the search patterns • Defined as a string composed of letters, numbers, and special symbols, that defines one or more strings • You have already used them in selecting files when you used asterisk (*) and question mark characters to select filenames • Used by several Unix utilities such as ed, vi, emacs, grep, sed, and awk to search for and replace strings – Checking the author, subject, and date of each message in a given mail folder egrep "ˆ(From|Subject|Date): " <folder> – The quotes above are not a part of the regular expression but are needed by the command shell – The metacharacter | (or) is a convenient one to combine multiple expressions into a single expression to match any of the individual expressions contained therein ∗ The subexpressions are known as alternatives • A regular expression is composed of characters, delimiters, simple strings, special characters, and other metacharacters defined below • Characters – A character is any character on the keyboard except the newline character ’\n’ – Most characters represent themselves within a regular expression – All the characters that represent themselves are called literals – A special character is one that does not represent itself (such as a metacharacter) and needs to be quoted ∗ The metacharacters in the example above (with egrep) are ", ˆ, (, |, and ) – We can treat the regular expressions as a language in which the literal characters -
User's Guide for Linux and UNIX
Centrify Server Suite User’s Guide for Linux and UNIX July 2021 (release 2021) Centrify Corporation • • • • • • Legal Notice This document and the software described in this document are furnished under and are subject to the terms of a license agreement or a non-disclosure agreement. Except as expressly set forth in such license agreement or non-disclosure agreement, Centrify Corporation provides this document and the software described in this document “as is” without warranty of any kind, either express or implied, including, but not limited to, the implied warranties of merchantability or fitness for a particular purpose. Some states do not allow disclaimers of express or implied warranties in certain transactions; therefore, this statement may not apply to you. This document and the software described in this document may not be lent, sold, or given away without the prior written permission of Centrify Corporation, except as otherwise permitted by law. Except as expressly set forth in such license agreement or non-disclosure agreement, no part of this document or the software described in this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, or otherwise, without the prior written consent of Centrify Corporation. Some companies, names, and data in this document are used for illustration purposes and may not represent real companies, individuals, or data. This document could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein. These changes may be incorporated in new editions of this document. Centrify Corporation may make improvements in or changes to the software described in this document at any time. -
Man Pages Section 2 System Calls
man pages section 2: System Calls Part No: E29032 October 2012 Copyright © 1993, 2012, Oracle and/or its affiliates. All rights reserved. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable: U.S. GOVERNMENT END USERS. Oracle programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are "commercial computer software" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of the programs, including anyoperating system, integrated software, any programs installed on the hardware, and/or documentation, shall be subject to license terms and license restrictions applicable to the programs. No other rights are granted to the U.S. Government. This software or hardware is developed for general use in a variety of information management applications. -
Intro to Unix-1-2014
Unix Introduction Getting started with the Unix Operating System What is an Operating System? A computer Operating System, or “OS” What is a computer operating system? Where? What does an OS provide? Insulation from hardware Allocation of resources Utility Functions (often blurring the line between OS and applications) The problem There are numerous past, present, and future storage technologies Each of these requires unique procedures for getting data to and from the device. But, it is unreasonable to expect each application to understand each device. The solution The OS provides simple "abstract devices” for storage: Random access (disks, solid state) Sequential access (tapes) Applications talk to the abstract devices, the OS translates and talks to the actual devices. The OS provides a layer of insulation from these details. Beyond storage Insulation roles of the OS extends to most aspects of computer hardware, including User interface devices Network and communications Memory Expansion busses … OS-Hardware pairing OS is necessarily closely tied to particular hardware. OS used to always be supplied by the hardware vendor. What does an OS provide? Insulation from hardware Allocation of resources Utility About that “disk” abstraction… The disk abstraction represents a disk as quantity of storage. An application is insulated from the hardware details of exactly how the data are stored. An application can read or write from any location in that quantity of storage. The problem The disk abstraction provides no structure for data stored in the disk. If multiple applications want to use the same disk, they must agree on a way to structure data. -
L01 – the Terminal • What Is a Terminal? O Command Line Interface with the Computer. Text Only. in the Old Days the Terminal
L01 – The Terminal • What is a terminal? o Command line interface with the computer. Text only. In the old days the terminal was the only interface to the computer. o Terminal, bash, shell, console, are all interchangeable words, as far as we’re concerned. o The terminal will be our programming environment, we won’t use IDE’s like Eclipse. • Using the terminal o Everything you can do using the Finder, such as navigate to different folders, open files, create files and directories, can also be done via the terminal. o Navigating the file system § “pwd” – present working directory; reports your current location in the file system § “cd <dir>” – change directory; goes into a specified directory § “ls” – list; lists the contents of your pwd • “ls –alF” – the options “-alF” lists all files (even hidden files) with extra information. § “.” and “..” – shortcuts that refer to current directory, and up one level directory • e.g.: “cd ..” takes you up one level. “cd .” takes your to the current directory, effectively does nothing. § “~” is a shortcut that refers to your home directory. For me its /Users/gregorychen3 o Making changes to the file system § “mkdir <name>” – make directory; creates a new directory (folder) called <name> § “cp <src> <dest>” – copy; copies file located at <src> to <dest>. Hint: use “.” and “..” shortcuts to specify the file paths § “mv <src> <dest>” – move; move a file located at <src> to <dest>. Hint: use “.” and “..” shortcuts to specify the file paths § “rm <file>” – remove; removes the file located at <file>. • “rm –r <dir>” – remove recursive; removes directory located at <dir>. -
Usability Improvements for Products That Mandate Use of Command-Line Interface: Best Practices
Usability improvements for products that mandate use of command-line interface: Best Practices Samrat Dutta M.Tech, International Institute of Information Technology, Electronics City, Bangalore Software Engineer, IBM Storage Labs, Pune [email protected] ABSTRACT This paper provides few methods to improve the usability of products which mandate the use of command-line interface. At present many products make command-line interfaces compulsory for performing some operations. In such environments, usability of the product becomes the link that binds the users with the product. This paper provides few mechanisms like consolidated hierarchical help structure for the complete product, auto-complete command-line features, intelligent command suggestions. These can be formalized as a pattern and can be used by software companies to embed into their product's command-line interfaces, to simplify its usability and provide a better experience for users so that they can adapt with the product much faster. INTRODUCTION Products that are designed around a command-line interface (CLI), often strive for usability issues. A blank prompt with a cursor blinking, waiting for input, does not provide much information about the functions and possibilities available. With no click-able option and hover over facility to view snippets, some users feel lost. All inputs being commands, to learn and gain expertise of all of them takes time. Considering that learning a single letter for each command (often the first letter of the command is used instead of the complete command to reduce stress) is not that difficult, but all this seems useless when the command itself is not known. -
The Linux Command Line
The Linux Command Line Second Internet Edition William E. Shotts, Jr. A LinuxCommand.org Book Copyright ©2008-2013, William E. Shotts, Jr. This work is licensed under the Creative Commons Attribution-Noncommercial-No De- rivative Works 3.0 United States License. To view a copy of this license, visit the link above or send a letter to Creative Commons, 171 Second Street, Suite 300, San Fran- cisco, California, 94105, USA. Linux® is the registered trademark of Linus Torvalds. All other trademarks belong to their respective owners. This book is part of the LinuxCommand.org project, a site for Linux education and advo- cacy devoted to helping users of legacy operating systems migrate into the future. You may contact the LinuxCommand.org project at http://linuxcommand.org. This book is also available in printed form, published by No Starch Press and may be purchased wherever fine books are sold. No Starch Press also offers this book in elec- tronic formats for most popular e-readers: http://nostarch.com/tlcl.htm Release History Version Date Description 13.07 July 6, 2013 Second Internet Edition. 09.12 December 14, 2009 First Internet Edition. 09.11 November 19, 2009 Fourth draft with almost all reviewer feedback incorporated and edited through chapter 37. 09.10 October 3, 2009 Third draft with revised table formatting, partial application of reviewers feedback and edited through chapter 18. 09.08 August 12, 2009 Second draft incorporating the first editing pass. 09.07 July 18, 2009 Completed first draft. Table of Contents Introduction....................................................................................................xvi -
Rc the Plan 9 Shell
Rc ߞ The Plan 9 Shell Tom Duff [email protected]−labs.com ABSTRACT Rc is a command interpreter for Plan 9 that provides similar facilities to UNIXߣs Bourne shell, with some small additions and less idiosyncratic syntax. This paper uses numerous examples to describe rcߣs features, and contrasts rc with the Bourne shell, a model that many readers will be familiar with. 1. Introduction Rc is similar in spirit but different in detail from UNIXߣs Bourne shell. This paper describes rcߣs principal features with many small examples and a few larger ones. It assumes familiarity with the Bourne shell. 2. Simple commands For the simplest uses rc has syntax familiar to Bourne-shell users. All of the fol lowing behave as expected: date cat /lib/news/build who >user.names who >>user.names wc <file echo [a−f]*.c who | wc who; date vc *.c & mk && v.out /*/bin/fb/* rm −r junk || echo rm failed! 3. Quotation An argument that contains a space or one of rcߣs other syntax characters must be enclosed in apostrophes (’): rm ’odd file name’ An apostrophe in a quoted argument must be doubled: echo ’How’’s your father?’ 4. Patterns An unquoted argument that contains any of the characters *?[is a pattern to be matched against file names. A * character matches any sequence of characters, ? matches any single character, and [class] matches any character in the class, unless the first character of class is ~, in which case the class is complemented. The class may 2 also contain pairs of characters separated by −, standing for all characters lexically between the two. -
Taskplaner 123RF ©Everydayplus
Know-how Cron-Alternativen Moderne Task-Scheduler: Fcron und Hcron Taskplaner 123RF ©everydayplus, Der Standard-Scheduler Cron Die meisten Rechner laufen nicht rund der nach dem Einschalten des Compu- um die Uhr, schon um Strom zu sparen. ters offene Routineaufgaben nachholt. ist inzwischen leicht ange- Trotzdem will man manche Aufgaben Dazu haben wir unter Fedora 29 die automatisiert in Zeiten abarbeiten, zu Scheduler Fcron und Hcron an- staubt. Mit Fcron und Hcron denen man nicht vor dem Computer hand des Programms Backup-Mana- sitzt: Es ist auf die Dauer mühsam, stän- ger auf Herz und Nieren getestet. gibt es modernere Alternati- dig das Backup manuell zu starten. Mit Die Konfiguration von Hcron behan- dem klassischen Scheduler Cron lassen delte bereits unsere Schwesterzeitschrift ven, jeweils mit spezifischen sich derartige Tasks automatisiert abwi- Raspberry Pi Geek ausführlich . Daher ckeln. Läuft allerdings zum vorgegebe- widmet sich dieser Artikel vorwiegend Anzela Minosi Vorteilen. nen Zeitpunkt der PC nicht, fällt die auto- Fcron, um zum Schluss die Vor- und matische Ausführung unter den Tisch. Nachteile beider Scheduler abzuwägen. Regelmäßige Aufgaben sollten Sie da- her lieber einem Scheduler überlassen, Listing 2 # dnf install python3 Listing 1 python3‑PyQt5 python3‑PyQt4 # dnf install gcc sendmail [...] [...] $ wget https://downloads. README $ wget http://fcron.free.fr/ sourceforge.net/project/fcronq/ FcronQ/0.5.0/FcronQ‑0.5.0.tar.bz2 Sowohl Hcron als auch Fcron eignen sich archives/fcron‑3.2.1.src.tar.gz $ tar xvf fcron‑3.2.1.src.tar.gz $ tar xvf FcronQ‑0.5.0.tar.bz2 für Computer, die nicht nonstop laufen. $ cd fcron‑3.2.1 $ cd FcronQ/Build/ Beide können Aufgaben planen und regel- $ ./configure $ make all $ make install‑user mäßig ausführen, für Fcron gibt es dazu so- $ gmake [...] [..