Luca's pills for computer vision and machine learning experiments on linux: linux

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Showing posts with label linux. Show all posts

Friday, August 15, 2014

how to migrate your mongodb into a bigger volume

First stop your mongodb

sudo service mongod stop

Assuming that your existing mongo installation is on /var/lib/mongodb/

sudo mv /var/lib/mongodb/ /your/preferred/destination/for/mongo/

set the rights correctly

sudo chmod -R mongodb.mongodb /your/preferred/destination/for/mongo/

and update the mongodb configuration file

# dbpath=/var/lib/mongodb 

dbpath= /your/preferred/destination/for/mongo/

Thursday, March 27, 2014

Notes on the most beautiful shell of the world: fish!




How do I run a command every login? What's fish's equivalent to .bashrc?



Edit the file ~/.config/fish/config.fish, creating it if it does not exist. (Note the leading period.)


How do I set my prompt?

The prompt is the output of the function fish_prompt. Put it in ~/.config/fish/config.fish, or in ~/.config/fish/functions/fish_prompt.fish. For example:

  function fish_prompt
    set_color $fish_color_cwd
    echo -n (prompt_pwd)
    set_color normal
    echo -n ' > '
  end

Thursday, March 21, 2013

calculate load of individual machines on a cluster

Use :

$ uptime

Output:

20:57:50 up 196 days, 1:36, 4 users, load average: 4.00, 4.00, 4.42

The load averages reported are system load averages for the last 1, 5 and 15 minutes respectively.

Note that a load average of 1 means there's enough work being done by the system to keep 1 CPU busy 100% of the time. (So either 1 process taking 100% or 2 processes taking each 50% etc.) A load average of 2 would likewise be enough to consume 100% of 2 CPU's. Etc.

Combine it with pssh to simultaneously check the load on multiple machines :

$ pssh -h ~/bin/spiders.pssh -o ./cluster.log "uptime"

Monday, March 18, 2013

command line emails from ubuntu

frome the excellent post of http://askubuntu.com/questions/12917/how-to-send-mail-from-the-command-line

Install ssmtp : sudo apt-get install ssmtp
Edit the ssmtp config file : gksu gedit /etc/ssmtp/ssmtp.conf
Enter this in the file:
root=username@gmail.com
mailhub=smtp.gmail.com:465
rewriteDomain=gmail.com
AuthUser=username
AuthPass=password
FromLineOverride=YES
UseTLS=YES

you can then use

mutt or mailx to send your emails from command line

Wednesday, March 13, 2013

script to rename directories / files with spaces

here's a small script that normalizes directory names by getting rid of empty spaces in the directory name. Worth is noticing that can be tweaked to remove other unwanted characters:

find -type d | \ find all the directories
grep " "\ get only the ones with a whitespace
| while read line; do\
mv -i ${line} \
`echo ${line} | sed 's@ @_@g' `\ replace the space
; done

in one line the commands for

normalizing directory names

find -type d | grep " " | while read line; do echo "[RUN]: Normalizing directory "${line}; mv -i ${line} `echo ${line} | sed 's@ @_@g' `; done | m

normalizing filenames

find * | grep " " | while read line; do echo "[RUN]: Normalizing filename "${line}; mv -i ${line} `echo ${line} | sed 's@ @_@g' `; done