Commands by lv4tech

Commands by lv4tech (10)

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Get acurate memory usage of a Process in MegaBytes
This is sample output - yours may be different.
1

pmap $(pgrep [ProcessName] -n) | gawk '/total/ { a=strtonum($2); b=int(a/1024); printf b};'

lv4tech · 2010-04-28 08:16:28 4
Test file system performance

You need bonnie++ package for this. More detail than a simple hdparm -t /dev/sda would give you. the -d is the directory where it performs writes/reads for example I use /tmp/scratch with 777 permissions Bonnie++ benchmarks three things: data read and write speed, number of seeks that can be performed per second, and number of file metadata operations that can be performed per second.
This is sample output - yours may be different.
6

bonnie++ -n 0 -u 0 -r <physical RAM> -s <2 x physical ram> -f -b -d <mounted disck>

lv4tech · 2009-09-18 09:46:44 10
display portion of a file

This is useful for displaying a portion of a FILE that contains an error at line NUMBER
This is sample output - yours may be different.
-1

cat -n FILE | grep -C3 "^[[:blank:]]\{1,5\}NUMBER[[:blank:]]"

lv4tech · 2009-05-17 18:19:55 8
List all PostgreSQL databases. Useful when doing backups
This is sample output - yours may be different.
3

psql -U postgres -lAt | gawk -F\| '$1 !~ /^template/ && $1 !~ /^postgres/ && NF > 1 {print $1}'

lv4tech · 2009-05-15 14:33:50 6
Get your public ip using dyndns
This is sample output - yours may be different.
17

curl -s http://checkip.dyndns.org/ | grep -o "[[:digit:].]\+"

lv4tech · 2009-05-14 09:43:31 15
List all system users
This is sample output - yours may be different.
-9

~<press tab twice>

lv4tech · 2009-05-12 17:33:33 12
Generate padded numbers 001 002 ... 100
This is sample output - yours may be different.
0

echo 00{1..9} 0{10..99} 100

lv4tech · 2009-05-07 21:08:53 10
Search for files older than 30 days in a directory and list only their names not the full path
This is sample output - yours may be different.
2

find /var/www/html/ -type f -mtime +30 -exec basename {} \;

lv4tech · 2009-05-07 21:05:47 6
Find out which version of linux you are running
This is sample output - yours may be different.
-6

cat /etc/*issue

lv4tech · 2009-05-07 20:53:03 10
Cloning hard disks over the network:

This is a bit to bit copy so if you have a 500GB hard disk it will take a long time even if have Gigabit Ethernet
This is sample output - yours may be different.
-1

Boot up destination machine with Knoppix live CD and run nc -l -p 9000 | dd of=/dev/sda Then on the master dd if=/dev/sda | nc <dest-ip> 9000 You can monitor bandwidth usage to see progress: nload eth0 -u M

lv4tech · 2009-05-07 05:26:58 6

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Monitor ElasticSearch cluster health - Useful for keeping an eye on ES when rebalancing takes place

Uniquely (sort of) color text so you can see changes

Colorify colors input by converting the text to a number and then performing modulo 7 on it. This resulting number is used as the color escape code. This can be used to color the results of commands with complex outputs (like "482279054165371") so if any of the digits change, there's a good chance the color will change too. I say good chance because there's only 7 unique colors here, so assuming you were watching random numbers, there would be a 6/7 chance that the color would change when the number changed. This should really only be used to help quickly identify when things change, but should not be the only thing relied upon to positively assert that an output has not changed.

Generate a random left-hand password

Generates a random 8-character password that can be typed using only the left hand on a QWERTY keyboard. Useful to avoid taking your hand off of the mouse, especially if your username is left-handed. Change the 8 to your length of choice, add or remove characters from the list based on your preferences or kezboard layout, etc.

Set a posix shell to echo all commands that it's about to execute, after all expansions have been done.

the 'set -x' mode can be exited by typing $ set +x

Remove color codes (special characters) with sed

Command to logout all the users in one command

Logs all users out except root. I changed the grep to use a regexp in case a user's username contained the word root.

Clean up after a poorly-formed tar file

These days, most software distributed in tar files will just contain a directory at the top level, but some tar files don't have this and can leave you with a mess of files in the current folder if you blindly execute $ tar zxvf something.tar.gz This command can help you clean up after such a mistake. However, note that this has the potential to do bad things if someone has been *really* nasty with filenames.

log your PC's motherboard and CPU temperature along with the current date

Uses the data in the /proc system, provided by the acpid, to find out the CPU temperature. Can be run on systems without lm-sensors installed as well.

Take screenshot through SSH

When connected to a box via ssh you can do a quick screenshot of that box using this command. After that you can rscp it over to your box and look at it.

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