Commands by dennisfaust (4)

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Schedule Nice Background Commands That Won't Die on Logout - Alternative to nohup and at
Check out the usage of 'trap', you may not have seen this one much. This command provides a way to schedule commands at certain times by running them after sleep finishes sleeping. In the example 'sleep 2h' sleeps for 2 hours. What is cool about this command is that it uses the 'trap' builtin bash command to remove the SIGHUP trap that normally exits all processes started by the shell upon logout. The 'trap 1' command then restores the normal SIGHUP behaviour. It also uses the 'nice -n 19' command which causes the sleep process to be run with minimal CPU. Further, it runs all the commands within the 2nd parentheses in the background. This is sweet cuz you can fire off as many of these as you want. Very helpful for shell scripts.

Get your commandlinefu points (upvotes - downvotes)
This will calculate the your commandlinefu votes (upvotes - downvotes). Hopefully this will boost my commandlinefu points.

move a lot of files over ssh
Useful to move many files (thousands or millions files) over ssh. Faster than scp because this way you save a lot of tcp connection establishments (syn/ack packets). If using a fast lan (I have just tested gigabyte ethernet) it is faster to not compress the data so the command would be: tar -cf - /home/user/test | ssh [email protected] 'cd /tmp; tar xf -'

Get the /dev/disk/by-id fragment for a physical drive
Substitute for #11720 Can probably be even shorter and easier.

Convert multiple pdf's to jpg in linux using the convert command

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

Copy via tar pipe while preserving file permissions (cp does not!; run this command with root!)
cp options: -p will preserve the file mode, ownership, and timestamps -r will copy files recursively also, if you want to keep symlinks in addition to the above: use the -a/--archive option

Get the list of root nameservers for a given TLD

Launch firefox on a remote linux server
Actually 'firefox' is a script that then launches the 'firefox-bin' executable. You need to specify the 'no-remote' option in order to launch remote firefox instead of your local one (this drove me crazy time ago)

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"


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