{"id":6480,"date":"2020-01-25T21:22:28","date_gmt":"2020-01-25T20:22:28","guid":{"rendered":"https:\/\/monodes.com\/predaelli\/?p=6480"},"modified":"2020-01-25T21:22:28","modified_gmt":"2020-01-25T20:22:28","slug":"advanced-cli-commands-you-should-know-as-a-developer","status":"publish","type":"post","link":"https:\/\/monodes.com\/predaelli\/2020\/01\/25\/advanced-cli-commands-you-should-know-as-a-developer\/","title":{"rendered":"Advanced CLI: Commands You Should Know as a Developer"},"content":{"rendered":"

\"\"<\/a> Advanced CLI: Commands You Should Know as a Developer<\/a><\/em><\/p>\n

May I feel a little proud when I tell you I know them all? \ud83d\ude42<\/p>\n

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Advanced CLI: Commands You Should Know as a Developer<\/h1>\n<\/div>\n<\/div>\n
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Advanced commands; get more done<\/h2>\n
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No, in this article we won\u2019t go over the basic commands like ls<\/code>, rm<\/code>, and cd<\/code>. You shouldn\u2019t be shocked by seeing those commands. You might even be quite familiar with them. Especially if you know your way around the command line pretty well. I assume you have at least worked (or tried to work) on the command line before. If you\u2019ve never worked on the command line before, I suggest you start by reading about the basics.<\/p>\n

This article is for those of you who have some experience with the command line and got a taste of the basic commands. For those who feel like it\u2019s time to dive deeper into the possibilities of working with the command line. I\u2019ve listed six commands for you in this article and included some tips at the bottom as well.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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1. wget<\/h1>\n

On Unix-like operating systems, the wget<\/code> command downloads files served with HTTP, HTTPS, or FTP over a network. By default, it is included in all self-respecting Linux distributions.<\/p>\n

The most simple way to use wget<\/code> is to provide it with the location of a file to download over HTTP. Downloading the file http:\/\/website.com\/static\/images\/header.jpg<\/code> with wget<\/code> can be done by the following command:<\/p>\n

wget http:\/\/website.com\/static\/images\/header.jpg<\/span><\/pre>\n
One great thing about wget<\/em> is that it\u2019s non-interactive, which means that it can run in the background while the user is not logged on. This allows you to start a retrieval and disconnect from the system, letting wget<\/code> finish the work.<\/p>\n<\/div>\n<\/div>\n<\/section>\n
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2. scp<\/h1>\n
Ever had a problem where you needed to have a file from a remote server on your local machine? Getting a file that a user uploaded that caused some trouble, for example.<\/p>\n
You could download this file via the command line using the scp<\/code> command. Scp is short for secure copy<\/em>. But what\u2019s even more important is that it\u2019s a remote<\/strong> secure copy. This command is similar to the cp<\/code> command that you probably already know, but either the source or the target is on another system.<\/p>\n
The following command copies the file foobar.txt<\/code> from a remote server to a local directory.<\/p>\n
scp username@remotehost.com:\/path\/to\/foobar.txt \/some\/local\/directory<\/span><\/pre>\n
But scp<\/code> can also be used to copy a file from a local directory to a remote server.<\/p>\n
scp \/some\/local\/directory\/foobar.txt username@remotehost.com:\/destination\/path\/<\/span><\/pre>\n
The same can be done with directories using the -r<\/code> option, which copies entire directories recursively.<\/p>\n<\/div>\n<\/div>\n<\/section>\n
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3. ssh-keygen<\/h1>\n
The ssh-keygen<\/code> command is used to generate a new SSH key pair. The public SSH key that is generated by this command can be used in Gitlab or Bitbucket to establish a secure connection.<\/p>\n
Once you\u2019ve added your SSH key to either Gitlab or Bitbucket, you won\u2019t be prompted for a password every time you try to push your files to a remote branch.<\/p>\n
To generate an SSH key pair, use the following command:<\/p>\n
ssh-keygen -t ed25519<\/span><\/pre>\n
Note that in the example above, we used the ED25519 signing algorithm. While ED25519 is considered best practice, you should always do some research on the different available signing algorithms.<\/p>\n
Generating the SSH key pair and setting it up correctly in Gitlab or Bitbucket costs you ten minutes at a maximum (probably more like three) but will be totally worth it!<\/p>\n<\/div>\n<\/div>\n<\/section>\n
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4. chmod<\/h1>\n
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In Unix and Unix-like operating systems, chmod is the command and system call which is used to change the access permissions of file system objects (files and directories).<\/p>\n<\/blockquote>\n
According to Wikipedia<\/a>, this is the definition of the chmod<\/code> command. We\u2019ve all been in a situation where a server didn\u2019t have access to a certain file because of a misconfiguration in the file permissions.<\/p>\n
The chmod<\/code> command is fairly simple in itself, but giving the right permissions to files and directories is a whole different game.<\/p>\n
chmod 664 robots.txt\nchmod 775 public\/images<\/span><\/pre>\n
The first example gives read and write permission to user and group for the robots.txt<\/code> file. Read permission is granted to others for this file.<\/p>\n
The second example gives read, write and execute permission to user and group for the public\/images<\/code> folder. Others are granted read and execute permission for this folder.<\/p>\n
If you want to know more about setting the right permissions to files and directories, I suggest you read the Wikipedia page about chmod<\/code>.<\/p>\n<\/div>\n<\/div>\n<\/section>\n
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5. tar<\/h1>\n
The Linux tar<\/code> stands for tape archive<\/em>. It is used for collecting many files into one archive file. Tar<\/code> is the most widely used command to create compressed archive files.<\/p>\n
Let\u2019s start with how you can create an archive file for a specific directory:<\/p>\n
tar -cvf my-archive.tar \/path\/to\/directory<\/span><\/pre>\n
This command will result in an archive file, called my-archive.tar<\/code>, that contains all files of the \/path\/to\/directory<\/code> which is created in the current working directory.<\/p>\n
Creating the archive file is part one. Part two consists of untarring the archive file, because at some point we want to use the files in the tar file. You can untar the file into a specific directory by typing in the following command:<\/p>\n
tar -xvf my-archive.tar -C \/home\/myfolder\/<\/span><\/pre>\n<\/div>\n<\/div>\n<\/section>\n
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6. alias<\/h1>\n
Everyone uses some commands that are a little too long or complex to completely remember. Luckily, you can create an alias<\/code> for that command so you don\u2019t have to remember the entire command.<\/p>\n
alias short-command=\"your custom and very long command here\"<\/span><\/pre>\n
Though creating an alias this way comes with one problem: This alias is temporary. If you create an alias this way, it will only be available for your current terminal session.<\/p>\n
To keep aliases between sessions, you can save them in your user\u2019s shell configuration profile file. This profile file is probably located at either ~\/.bashrc<\/em> or ~\/.zshrc<\/em> if you\u2019re using Bash or ZSH, respectively.<\/p>\n<\/div>\n<\/div>\n<\/section>\n
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Tip 1: Directing Output<\/h1>\n
The standard output device is the screen. But sometimes you don\u2019t want to output everything on your screen. In some cases, you probably prefer to output the results of some commands to a file. For logging purposes, for example.<\/p>\n
To redirect the output, you can use the <\/mark>>.<\/em><\/mark> In the following command, the output of <\/mark>ls -al<\/code><\/mark> is redirected to the file <\/mark>myfile<\/code><\/mark> instead of the screen.<\/mark><\/p>\n
ls -al > myfile<\/span><\/pre>\n
I\u2019ve used ls<\/code> in this example, but it really could be any command that has some output. To confirm that this worked, you can check the myfile<\/code> file.<\/p>\n
cat myfile<\/span><\/pre>\n<\/div>\n<\/div>\n<\/section>\n
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Tip 2: Combining Commands<\/h1>\n
It\u2019s possible to run two or more commands at once. The semicolon (;) operator allows you to do this. You can execute multiple commands in succession, regardless of whether each previous command succeeds.<\/p>\n
ls -al; pwd;<\/span><\/pre>\n
If you want the second command to only run if the first command is successful, separate the commands with the logical AND<\/em> operator, which is <em class="ks">&&<\/em><\/code>.<\/p>\n
mkdir images && cd images<\/span><\/pre>\n
We only want to cd<\/code> to the images<\/code> folder if we managed to create that folder.<\/p>\n
And sometimes you might want to execute a second command only if the first command does not <\/strong>succeed. To do this, we use the logical OR<\/em> operator, which is <em class="ks">||<\/em><\/code>.<\/p>\n<\/div>\n<\/div>\n<\/section>\n<\/div>\n<\/article>\n
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Better Programming<\/h2>\n
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Advice for programmers.<\/h4>\n<\/div>\n
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<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"
Advanced CLI: Commands You Should Know as a Developer May I feel a little proud when I tell you I know them all? \ud83d\ude42<\/p>\n
Read more →<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"link","meta":{"inline_featured_image":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[72],"tags":[],"class_list":["post-6480","post","type-post","status-publish","format-link","hentry","category-documentations","post_format-post-format-link"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6daft-1Gw","jetpack-related-posts":[{"id":9917,"url":"https:\/\/monodes.com\/predaelli\/2022\/12\/14\/how-to-become-a-command-line-wizard\/","url_meta":{"origin":6480,"position":0},"title":"How to become a command-line wizard","author":"Paolo Redaelli","date":"2022-12-14","format":false,"excerpt":"Dudes, I already use the tricks described in \u00abHow to become a command-line wizard\u00bb. 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