Commands by tduvally

Commands by tduvally (4)

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Change active bond slave

This forces a bonded interface to switch to another slave in the bond as its active slave.
This is sample output - yours may be different.
1

/sbin/ifenslave -c bond0 eth1

tduvally · 2013-02-06 16:04:35 11
Run a command on all servers using func

Using "func" to run any command and receive output from all your systems. Default output from func is normally meant for further script parsing, but is generally readable. This example shows system arch, but any command can be used and will run as typed. Show Sample Output
This is sample output - yours may be different.
```
('host1.example.com', [0, 'x86_64\n', ''])
('host2.example.com', [0, 'x86_64\n', ''])
('host3.example.com', [0, 'x86_64\n', ''])
```
0

func "*" call command run "uname -i"

tduvally · 2012-07-23 13:32:32 4
Change the primary group of a user
This is sample output - yours may be different.
2

usermod -g group user

tduvally · 2012-05-24 12:39:46 6
Simple file wipe

This will find any regular file starting with the current directory and use /dev/urandom to overwrite that file. It will is the same size of the file (in blocks) as the file. Can't handle files with spaces or odd characters in the name (who does that anyway?)
This is sample output - yours may be different.
0

for F in `find ./ -type f`;do SIZE=`ls -s $F | awk -F" " '{print $1}'`; dd if=/dev/urandom of=$F bs=1024 count=$SIZE;done

tduvally · 2011-08-19 18:50:27 5

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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"

Extract raw URLs from a file

you can also use cut instead of awk. less powerful but probably faster. ;)

drop first column of output by piping to this

Find ulimit values of currently running process

When dealing with system resource limits like max number of processes and open files per user, it can be hard to tell exactly what's happening. The /etc/security/limits.conf file defines the ceiling for the values, but not what they currently are, while $ ulimit -a will show you the current values for your shell, and you can set them for new logins in /etc/profile and/or ~/.bashrc with a command like: $ ulimit -S -n 100000 >/dev/null 2>&1 But with the variability in when those files get read (login vs any shell startup, interactive vs non-interactive) it can be difficult to know for sure what values apply to processes that are currently running, like database or app servers. Just find the PID via "ps aux | grep programname", then look at that PID's "limits" file in /proc. Then you'll know for sure what actually applies to that process.

convert Decimal to IP from stdin

https://stackoverflow.com/questions/10768160/ip-address-converter

Fibonacci With Case

Returns the '$1'th Fibonacci number.

how to export a table in .csv file

Exports the result of query in a csv file

list block devices

Shows all block devices in a tree with descruptions of what they are.

Determine next available UID

Typical usage would be in a script that would want the next open UID in a range (in this case 500-600)

Count opening and closing braces in a string.

This function counts the opening and closing braces in a string. This is useful if you have eg long boolean expressions with many braces and you simply want to check if you didn't forget to close one.

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

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