Commands by liushuililuo (2)

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Format partition with ext4 but without a journal
For slow flash memory (cheap thumb drive), ext4 is the fastest stable file system for all use cases with no relevant exception: http://www.linuxplanet.com/linuxplanet/tutorials/7208/1 Since we can usually dispense with the benefits of a journal for this type of storage, this is a way to achieve the least awful I/O-speed. Disabling the journal for an existing ext4 partition can be achieved using $ tune2fs -O ^has_journal /dev/sdXN Note that it is often recommended to format removable flash media with ext2, due to the lack of a journal. ext4 has many advantages over ext2 even without the journal, with much better speed as one of the consequences. So the only usecase for ext2 would be compatibility with very old software.

To find the uptime of each process-id of particular service or process

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

open two files on top of each other in vim (one window, two panes)

Check syntax of all Perl modules or scripts underneath the current directory
Finds all *.p[ml]-files and runs a perl -c on them, checking whether Perl thinks they are syntactically correct

Find running binary executables that were not installed using dpkg
This helped me find a botnet that had made into my system. Of course, this is not a foolproof or guarantied way to find all of them or even most of them. But it helped me find it.

How To Get the Apache Document Root

check open ports without netstat or lsof

Limit the transfer rate and size of data over a pipe
This example will close the pipe after transferring 100MB at a speed of 3MB per second.

Pull Total Memory Usage In Virtual Environment
This command basically adds up all of the individual instances processes and gives you a grand total for used memory in that instance alone.


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