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How to Grep for Multiple Words, Strings and Patterns

How to Grep for Multiple Words Strings and Patterns 1

This guide explains how to use the grep utility for searching multiple words, strings, and patterns. You can find full examples of the commands used to accomplish this below. What Is Grep? When we refer to grep, we’re talking about the command-line function. Grep stands for Global Regular Expression Print. In essence, it will search input files looking for lines that are a match to a certain regular expression. It then returns results by writing each line for standard output. The grep utility is suitable … Read more

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How to Get CPU Information on Linux

how to get cpu information linux

Within your computer, the central processing unit, aka the CPU, is a critical component. Despite its essential nature in performing countless data processing functions, many of us likely know very little about the CPU, hidden away inside the computer out of sight as it works its magic. Thankfully, finding CPU information on Linux systems is fairly straightforward, so let’s take a look at how it’s done. Why You Might Need CPU Information There are a few reasons why someone may want to obtain further CPU … Read more

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Tiny bash scripts: check Internet connection availability

Sometimes it is necessary to check whether server you want to run some big bash script is connected to Internet. Usually it makes sense while running scripts periodically using cron.  Below is the tiny bash script for this purpose: #!/bin/bash WGET=”/usr/bin/wget” $WGET -q –tries=10 –timeout=5 http://www.google.com -O /tmp/index.google &> /dev/null if [ ! -s /tmp/index.google ];then echo “no” else echo “yes” fi As you see it tries to download google’s index page, if it’s not empty script returns “yes”, if there is not Internet connection … Read more

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Create Linux user with password

Sometimes it’s necessary to create Linux user accounts in batch mode (fully automatic) but often newbies ask how to set password for a new user without entering it manually. Thanks to heaven command useradd can get password as an input parameter, but it should be encrypted. In other words, to create Linux user account with password the following command will be useful: useradd -m -p encryptedPass username I know at least two ways to get password encrypted. The first one is to use perl crypt(); … Read more

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Find out where Unix/Linux executable binary is located

There are two commands that may help you to find where executable binary is located regardless it’s Unix or Linux system. They are whereis and type. First locates source/binary and manuals sections for specified files and second tells what exactly shell executes when you type a certain command. The next picture shows examples of these commands work.