Fastfetch grabs your system's info and then displays it appealingly. It is written mainly in C, with performance and customizability in mind.
Fastfetch includes two executables; Fastfetch, which can be configured via flags. These flags can be made persistent in $XDG_CONFIG_HOME/fastfetch/config.conf. To view the available options, run fastfetch --help. The second executable is flashfetch. This one is configured at compile time to eliminate any possible overhead. Configuration can be very accomplished in src/flashfetch.c.
Fastfetch is constantly being developed with more and more options coming, and on slow machines, this might actually make a difference.
There are some premade config files in presets. You can load them using --load-config . They may also serve as a good example for format arguments.
Logos can be heavily customized. See the logo documentation for more information available at the developer repository for details.
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Fastfetch is an Open Source multi-platform app capable of quickly fetching and displaying system info.