Working with Linux

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If we run our script with the arguments a b c, we can see that our while looped through the parametersand printed each one on a separate line. Now let's extend our CLI arguments parser and add a casestatement for interpreting the arguments.Let's assume that our script will have a help option. The Posix standard recommends doing a longargument version with --, and a short version with only one -. So both -h and --help will print thehelp message. Also, it is recommended to always have a default case and print a message when theuser sends invalid options and then exits with a non-zero exit value:while [[ ! -z ${1} ]]; docase "$1" in--help|-h)echo "This is a help message"shift;;*)
esacdoneecho "invalid option"exit 1;;If we run our script with -h, we can see the help message printed, the same as if we had used --help.If we run the script with any other option, the invalid option text is printed and the script exits withthe exit code 1. To get the exit code of the last command, use "$?".Now let's look at basic functions in shell. The syntax is pretty similar to other programminglanguages. Let's write a function called print_ip that will print the IP of the interface specified asthe first argument. We will use a subshell and assign the value to a variable called IP. We alreadyhave the full command inside our clipboard; it's the same one we saw in the lesson about pipes:function print_ip() {
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Working with Linux - Quick Hacks fo
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Network - Who's listening?Autoenv -
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Working with Linux - Quick Hacks fo
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Melwyn DsaCover WorkMelwyn Dsa
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www.PacktPub.com
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Why subscribe?Fully searchable acro
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PrefaceOur mission is to save Linux
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What you need for this bookIdeally,
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ConventionsIn this book, you will f
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Customer supportNow that you are th
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PiracyPiracy of copyrighted materia
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Chapter 1. IntroductionThis book is
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Terminator - the ultimate terminalT
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Preferences menuIt's an customizing
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And voila! This is our newly config
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Ctrl + Shift + E for a vertical spl
Page 35 and 36: Text zoom: Ctrl + + and Ctrl + -
Page 37 and 38: Guake - not Quake!Terminator works
Page 39 and 40: I believe you can guess what this d
Page 41 and 42: We can use Guake in full screen by
Page 43 and 44: The tool is automatically added to
Page 45 and 46: For example, we might want to updat
Page 47 and 48: With ClipIt, you can copy and paste
Page 49 and 50: Vim is renowned for its exotic keyb
Page 51 and 52: Press the Insert key again to go to
Page 53 and 54: productive in the coolest terminal
Page 55 and 56: instructions for installing the oh-
Page 57 and 58: Let's create a file, say readme.md.
Page 59 and 60: You can now see the branch name in
Page 61 and 62: History navigation: Click on arrow
Page 63 and 64: To see a list of shortcuts, run the
Page 65 and 66: joe is the string we are searching
Page 67 and 68: If we don't know exactly what chara
Page 69 and 70: To find all the lines that have onl
Page 71 and 72: This will replace every occurrence
Page 73 and 74: Pipes and subshells - your shell's
Page 75 and 76: "df -h": This shows the disk usage
Page 77 and 78: ps aux: This prints all processes w
Page 79 and 80: cat lorem.txt| tr " " "\n": Transfo
Page 81 and 82: imagination and how well you learn
Page 83 and 84: As you can see, the value test is p
Page 85: In our case, we will be selecting f
Page 89 and 90: ./script.sh --ip wlp3s0We can see t
Page 91 and 92: This way we can start the script, w
Page 93 and 94: Shell scripting librariesTo really
Page 95 and 96: of the current working directory (o
Page 97 and 98: case ${CMD} inpublicip)print_public
Page 99 and 100: Supercharging VimLet's start by ope
Page 101 and 102: Let's choose desert!
Page 103 and 104: We can do the same thing for xml fi
Page 105 and 106: Keyboard kung fuNow that we have Vi
Page 107 and 108: Other handy shortcuts are:G: Go to
Page 109: :1,$s/CWD/DIR/g:1,$ - start from li
Page 112 and 113: This will delete everything from li
Page 114: cat lorem.txt | tr " " "\n" | grep
Page 117 and 118: When Vim splits the screen, it open
Page 119 and 120: Plugin steroids for VimIn this sect
Page 121 and 122: As we can see, before installing sn
Page 123 and 124: Here we can see all the snippets av
Page 125 and 126: A page describing the different enc
Page 127 and 128: It also has the benefit that it's s
Page 129 and 130: Using heredocs is a common techniqu
Page 131 and 132: Sed - one-liner productivity treasu
Page 133 and 134: If we check the content of the file
Page 135 and 136: As you can see, the text was update
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You can run, but you can't hide…
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You see here that both readme.md an
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You can see here all files that don
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Find can also locate files based on
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A good folder to search is ~/.local
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As we can see, electron has a few e
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In order to do this, we combine fin
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tmux - virtual consoles, background
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For demonstration purposes, we will
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This will kill the running session.
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You also have the possibility to cr
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Ctrl + b &: delete
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Network - Who's listening?When work
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Other useful information we get fro
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You can quickly understand the form
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As you can see, there is again the
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non-standard. To actually connect t
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hostnames and ports. For a deeper u
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Now let's do the same thing for pro
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autoenv: Are you sure you want to a
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export environment=devexport versio
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Autoenv can really come in handy, a
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Let's assume we don't need the file
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It will show us a list of options a
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Chapter 5. Developers' TreasureIn t
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Clicking on the button generates a
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You can find the files used in this
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The first and most important part o
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The format of the output image will
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This will create a JPEG image with
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Let's try to shrink the large PNG i
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Alright, now let's try and do the s
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Go with the Git flowGit is by far t
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We can see that we are now on the d
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This command will tell us that we h
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This switches us over to our releas
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We see that the only two available
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GitFlow also comes with an enhanced
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Analyzing the git hooks directory,
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Merging Git conflicts with easeNow
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After this, we can run the followin
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Now we can easily see the two files
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In general, most modern IDEs offer
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Now do a rehash and type the follow
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Click on the link provided by ngrok
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JSON jamming in the new ageNowadays
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If we want to grab the request meth
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If we want to use the output as inp
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Say, for example, if we want to cal
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Since that the syntax for accessing
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To skip printing empty bodies, we c
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We can even perform arithmetic oper
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There we can see an example of cons
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This will send gedit to the backgro
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Now we see that the mouse pointer h
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Chapter 6. Terminal ArtAll work and
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To make this recurrent, we can incl
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Now, with our newly learned skills,
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Let your friends be amazed by the c
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IndexAautoenvabout / Autoenv - Set
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Ddesert / Color scheme desertdigabo
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Ffind commandusing / You can run, b
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Iidentify / Shrinking spells and ot
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LlinuxURL, for developers / Are you
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NNERDtreeabout / Plugin steroids fo
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PpathogenURL / Plugin steroids for
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Ssedone-liner productivity / Sed -
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VVimsupercharging / Supercharging V
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