Open-source News

Create bookmarks for your PDF with pdftk

opensource.com - Wed, 01/05/2022 - 16:01

In introducing pdftk-java, I explained how I use the pdftk-java command to make quick, often scripted, modifications to PDF files.


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Google Has Been Quietly Developing "GFR" To Debug Vulkan GPU Hangs/Crashes

Phoronix - Wed, 01/05/2022 - 16:00
Last year Google quietly open-sourced the Graphics Flight Recorder (GFR) for sorting out GPU hangs and crashes. GFR is implemented as an implicit Vulkan layer that works on both Windows and Linux...

5 ways to learn the C programming language in 2022

opensource.com - Wed, 01/05/2022 - 16:00

I am proficient in several programming languages, but my favorite has to be C. Developed in the 1970s as a systems programming language, C remains one of the most popular programming languages in 2021. If you'd like to explore several features of the C programming language, start with these popular articles from the last year:

Short option parsing using getopt in C


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How to Block SSH Brute Force Attacks Using SSHGUARD

Tecmint - Wed, 01/05/2022 - 13:48
The post How to Block SSH Brute Force Attacks Using SSHGUARD first appeared on Tecmint: Linux Howtos, Tutorials & Guides .

SSHGuard is an open-source daemon that shields hosts from brute-force attacks. It accomplishes this through monitoring and aggregation of system logs, detecting attacks, and blocking attackers using one of the Linux firewall backends: iptables,

The post How to Block SSH Brute Force Attacks Using SSHGUARD first appeared on Tecmint: Linux Howtos, Tutorials & Guides.

Red Hat Smart Management for SAP

Red Hat News - Wed, 01/05/2022 - 13:00

Red Hat Smart Management for SAP is about automating the whole update process SAP hosts according to policies that can be defined by the administrators, which can save time and frustration. Learn more in this post.

Zink Working On Sparse Textures, Other Improvements To Kick Off 2022

Phoronix - Wed, 01/05/2022 - 13:00
After taking a roughly month-long holiday, Mike Blumenkrantz -- who has been leading the work on Mesa's Zink generic OpenGL-on-Vulkan implementation for Valve -- is back at the game...

Chrome 97 Released With WebTransport API

Phoronix - Wed, 01/05/2022 - 07:29
Google this afternoon promoted the Chrome 97 web browser to its stable series...

New Patches Help WineD3D Performance - Doubled FPS In Some Micro-Benchmarks

Phoronix - Wed, 01/05/2022 - 03:26
While most Linux gamers are making use of DXVK these days for efficiently mapping Direct3D 9/10/11 over Vulkan when running Wine/Proton for enjoying Windows games on Linux, Wine developers still maintain WineD3D for going from Direct3D to OpenGL for cross-platform compatibility. Out today is a new patch series improving the WineD3D performance...

Classic SysAdmin: How to Search for Files from the Linux Command Line

The Linux Foundation - Wed, 01/05/2022 - 03:00

This is a classic article written by Jack Wallen from the Linux.com archives. For more great SysAdmin tips and techniques check out our free intro to Linux course.

It goes without saying that every good Linux desktop environment offers the ability to search your file system for files and folders. If your default desktop doesn’t — because this is Linux — you can always install an app to make searching your directory hierarchy a breeze.

But what about the command line? If you happen to frequently work in the command line or you administer GUI-less Linux servers, where do you turn when you need to locate a file? Fortunately, Linux has exactly what you need to locate the files in question, built right into the system.

The command in question is find. To make the understanding of this command even more enticing, once you know it, you can start working it into your Bash scripts. That’s not only convenience, that’s power.

Let’s get up to speed with the find command so you can take control of locating files on your Linux servers and desktops, without the need of a GUI.

How to use the find command

When I first glimpsed Linux, back in 1997, I didn’t quite understand how the find command worked; therefore, it never seemed to function as I expected. It seemed simple; issue the command find FILENAME (where FILENAME is the name of the file) and the command was supposed to locate the file and report back. Little did I know there was more to the command than that. Much more.

If you issue the command man find, you’ll see the syntax of the find command is:

find [-H] [-L] [-P] [-D debugopts] [-Olevel] [starting-point...] [expression]

Naturally, if you’re unfamiliar with how man works, you might be confused about or overwhelmed by that syntax. For ease of understanding, let’s simplify that. The most basic syntax of a basic find command would look like this:

find /path option filename

Now we’ll see it at work.

Find by name

Let’s break down that basic command to make it as clear as possible. The most simplistic  structure of the find command should include a path for the file, an option, and the filename itself. You may be thinking, “If I know the path to the file, I’d already know where to find it!”. Well, the path for the file could be the root of your drive; so / would be a legitimate path. Entering that as your path would take find longer to process — because it has to start from scratch — but if you have no idea where the file is, you can start from there. In the name of efficiency, it is always best to have at least an idea where to start searching.

The next bit of the command is the option. As with most Linux commands, you have a number of available options. However, we are starting from the beginning, so let’s make it easy. Because we are attempting to find a file by name, we’ll use one of two options:

  • name – case sensitive

  • iname – case insensitive

Remember, Linux is very particular about case, so if you’re looking for a file named Linux.odt, the following command will return no results.

find / -name linux.odt

If, however, you were to alter the command by using the -iname option, the find command would locate your file, regardless of case. So the new command looks like:

find / -iname linux.odt Find by type

What if you’re not so concerned with locating a file by name but would rather locate all files of a certain type? Some of the more common file descriptors are:

  • f – regular file

  • d – directory

  • l – symbolic link

  • c – character devices

  • b – block devices

Now, suppose you want to locate all block devices (a file that refers to a device) on your system. With the help of the -type option, we can do that like so:

find / -type c

The above command would result in quite a lot of output (much of it indicating permission denied), but would include output similar to:

/dev/hidraw6 /dev/hidraw5 /dev/vboxnetctl /dev/vboxdrvu /dev/vboxdrv /dev/dmmidi2 /dev/midi2 /dev/kvm

Voilà! Block devices.

We can use the same option to help us look for configuration files. Say, for instance, you want to locate all regular files that end in the .conf extension. This command would look something like:

find / -type f -name "*.conf"

The above command would traverse the entire directory structure to locate all regular files ending in .conf. If you know most of your configuration files are housed in /etc, you could specify that like so:

find /etc -type f -name “*.conf”

The above command would list all of your .conf files from /etc (Figure 1).

 

Figure 1: Locating all of your configuration files in /etc.

Outputting results to a file

One really handy trick is to output the results of the search into a file. When you know the output might be extensive, or if you want to comb through the results later, this can be incredibly helpful. For this, we’ll use the same example as above and pipe the results into a file called conf_search. This new command would look like: ​

find /etc -type f -name “*.conf” > conf_search

You will now have a file (conf_search) that contains all of the results from the find command issued.

Finding files by size

Now we get to a moment where the find command becomes incredibly helpful. I’ve had instances where desktops or servers have found their drives mysteriously filled. To quickly make space (or help locate the problem), you can use the find command to locate files of a certain size. Say, for instance, you want to go large and locate files that are over 1000MB. The find command can be issued, with the help of the -size option, like so:

find / -size +1000MB

You might be surprised at how many files turn up. With the output from the command, you can comb through the directory structure and free up space or troubleshoot to find out what is mysteriously filling up your drive.

You can search with the following size descriptions:

  • c – bytes

  • k – Kilobytes

  • M – Megabytes

  • G – Gigabytes

  • b – 512-byte blocks

Keep learning

We’ve only scratched the surface of the find command, but you now have a fundamental understanding of how to locate files on your Linux systems. Make sure to issue the command man find to get a deeper, more complete, knowledge of how to make this powerful tool work for you.

The post Classic SysAdmin: How to Search for Files from the Linux Command Line appeared first on Linux Foundation.

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