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easily find megabyte eating files or directories
sorts the files by integer megabytes, which should be enough to (interactively) find the space wasters. Now you can $ dush for the above output, $ dush -n 3 for only the 3 biggest files and so on. It's always a good idea to have this line in your .profile or .bashrc

ubuntu tasksel
The command tasksel allows the choice of packages from the command line to get predefined configurations for specific services (usually this option is offered during installation).

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Easy to extend one-liner for cron scripts that automate filesystem checking
This one-liner is for cron jobs that need to provide some basic information about a filesystem and the time it takes to complete the operation. You can swap out the di command for df or du if that's your thing. The |& redirections the stderr and stdout to the mail command. How to configure the variables. TOFSCK=/path/to/mount FSCKDEV=/dev/path/device or FSCKDEV=`grep $TOFSCK /proc/mounts | cut -f1 -d" "` MAILSUB="weekly file system check $TOFSCK "

Set laptop display brightness
Run as root. Path may vary depending on laptop model and video card (this was tested on an Acer laptop with ATI HD3200 video). $ cat /proc/acpi/video/VGA/LCD/brightness to discover the possible values for your display.

Silently deletes lines containing a specific string in a bunch of files
This command will find all occurrences of one or more patterns in a collection of files and will delete every line matching the patterns in every file

Host cpu performance
Measure the cpu performance: In-case if the cpu is thermal throttling then you can find it using this command. Check the first line of the output. Example: Doing md5 for 3s on 16 size blocks: 11406892 md5's in 2.98s ? #(When cpu is not throttling) Doing md5 for 3s on 16 size blocks: 110692 md5's in 2.98s ?? #(When cpu is thermal throttling) Practical use case: Once we had cooling outage in data center which caused thermal throttling in some of the worker nodes. We used this tool to prove that some servers are not performing well because of the cpu thermal throttling.

Find default gateway

Find all files containing a word
This command will find all files recursively containing the phrase entered, represented here by "searchphrase". This particular command searches in all php files, but you could change that to just be html files or just log files etc.

tar pipe to copy files, alternate to cp -Ra
uses tar to dump files from /orignl/path to /dst/dir. i find tar's out more readable than cp, and it doesn't mess with modified dates.


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