imagemagick - add date on image

Install

sudo apt install imagemagick

example for batch mark date on images

for img in *.jpg;
do convert "$img" -gravity SouthEast -pointsize 64 -fill white -annotate +30+30 %[exif:DateTimeOriginal] "time_""$img";
done

Atom - source editor

Atom - excellent source editor under Linux, the most import thing is it's "FREE"

Install

sudo add-apt-repository ppa:webupd8team/atom sudo apt-get update sudo apt-get install atom

Ignored names (useful for search)

.git, .hg, .svn, .DS_Store, ._*, Thumbs.db, *.txt, *.tags, tags, *.stack, _out, *.htm, *.lst, .tags1

Best Packages for developers

Atom-ctags
Atom Beautify
File-icons
Highlight-line
Highlight-selected
Project-Manager
Symbol-tree-view
Terminal-plus
Vertical-tabs
Merge-conflicts
Todo-show
git-blame

SSD Optimization under Ubuntu

Reduce flush frequency

Add "noatime" on /etc/fstab UUID=f0ae2c59-83d2-42e7-81c4-2e870b6b255d / ext4 noatime,errors=remount-ro 0 1

Reserve some space for Over-provision

leave at least 7% capacity size for unformatted. (14 % is better)

Enable TRIM suuport

By default, Ubunut 16.04 will support trim operation automatically, but you could perform it manually

Reference

https://sites.google.com/site/easylinuxtipsproject/ssd

PS. Trust me, I have over 6 years experience on SSD firmware development.

Static code analysis - pylint

popular static code analysis for python language

Install (via pip)

pip install pylint

Run pylint

pylint [SOURCE]
Don't like command line tool? try pylint-gui pylint-gui

Python package installer

For all python developer, you will need it

for python 2.x

sudo apt install python-pip

for python 3.x

sudo apt install python3-pip

Static code analysis - flawfinder

Unlike cpecheck, flawfinder will looking for the security vulnerability of your source code

Install

sudo apt install flawfinder

Run flawfinder

flawfinder --html --quiet --dataonly . >> output.html

Reference

https://security.web.cern.ch/security/recommendations/en/codetools/flawfinder.shtml

Static code analysis - cppcheck

Great static code analysis tool for C/C++ programming language

Install

sudo apt install cppcheck

Run cppcheck and redirect result to output file

cppcheck --enable=all --force -j4 . 2> output

run cppcheck with html report

cppcheck --enable=all --inconclusive --xml-version=2 --force --library=windows,posix,gnu [PATH_TO_SOURCE] 2> result.xml && cppcheck-htmlreport --title="Your Project Name" --source-dir=[PATH_TO_SOURCE] --report-dir=[OUTPUT_DIR] --file=result.xml && rm result.xml Would like to try latest version of cppcheck? just clone the source from github https://github.com/danmar/cppcheck.git for more detailed information, please visit the home page https://github.com/danmar/cppcheck

Reference

https://sites.google.com/site/opensourceconstriubtions/ettl-martin-1/tutorials/how-to-generate-an-html-report-with-doxygen-using-the-linux-command-line-interface

Run 32 Bits program on Ubuntu 64 Bits

Sometimes, you might need to run 32 bits program under 64 bits environment. Here are the packages you need sudo apt install primus-libs-ia32 sudo apt install gcc-multilib sudo apt install lsb

hdparm - Sorage Device Configuration Tool

Official Website: hdparm

hdparm is a powerful and open source storage device configuration tool under Unix/Linux system. Here are the parameters I frequently used.

• Identify Devicehdparm -I /dev/sdb
• SecureErase hdparm --user-master u --security-set-pass p /dev/sdb
  hdparm --user-master u --security-erase p /dev/sdb
  hdparm --user-master u --security-unlock p /dev/sdb
  hdparm --user-master u --security-disable p /dev/sdb
• Set Maximum Sector (84GB / 128GB)hdparm -N p164115504 --yes-i-know-what-i-am-doing /dev/sdb

To pursue higher performance, storage device might implement data caching (store in the internal DRAM). However, it might have the risk of data loss, especially when a power failure occurred. For data protection purpose, we could disable write cache to prevent data loss disaster. Here are the steps for disabling write cache.
Disable Write Cache(Assume your device mounted on /dev/sdb) hdparm -W 0 /dev/sdb Enable Write Cache hdparm -W 1 /dev/sdb Once you disable the write cache, the performance will drop sharply!!!

Linux S3/S4 testing tool - rtcwake

Source: lpmt.c

If you are looking for a S3/S4 testing program under Linux OS. Here is a simple example to demonstrate how to do it by rtc

Compile:
gcc -o lpmt lpmt.c

Run:  (S3 for 100 cycles)
sudo ./lpmt S3 100
use it at your own risk :)

Ubuntu menu editor - alacarte

very useful tool sudo apt install alacarte

Equation Editor: LaTeX - Equalx

Install qeualx sudo apt install equalx List of LaTeX mathematical symbols

Ubuntu module blacklist

Edit blacklist.conf sudo gedit /etc/modprobe.d/blacklist.conf Add below statement at the end of the blacklist.conf blacklist [module name] Update ramfs and reboot sudo update-initramfs -u sudo reboot

Linux and Unix grep command

memo for frequently used command grep -nr "pattern you looking for" . Linux and Unix grep command

Change fonts on Ubuntu

Install unity-tweak-tool sudo apt install unity-tweak-tool

Install R on Ubuntu 16.04

Add R repository

sudo echo "deb http://cran.rstudio.com/bin/linux/ubuntu xenial/" | sudo tee -a /etc/apt/sources.list

Add R to Ubuntu Keyring

gpg --keyserver keyserver.ubuntu.com --recv-key E084DAB9 gpg -a --export E084DAB9 | sudo apt-key add -

Install R-base

sudo apt-get update sudo apt-get install r-base r-base-dev

Install GUI tool - Rstudio

sudo apt-get install gdebi-core wget https://download1.rstudio.org/rstudio-0.99.896-amd64.deb sudo gdebi -n rstudio-0.99.896-amd64.deb rm rstudio-0.99.896-amd64.deb

[Ubutnu] analyze system boot time

Simply execute the following command to see the detailed boot up time systemd-analyze blame

[Ubutnu] Create bridged network for qemu

Simple way to create bridged network between Ubuntu host and qemu client Install bridge-utils package first. sudo apt-get install bridge-utils Edit /etc/network/interfaces, and append the following configurations. Add a bridged network (br0) to your host network adapter (eth0)
------------------------
auto br0
iface br0 inet dhcp
 bridge_ports eth0
 bridge_stp off
 bridge_fd 0
 bridge_maxwait 0
------------------------
Restart your network. sudo /etc/init.d/networking restart Edit your script to boot qemu client, here is an example (-net nic, -net bridge,br=br0) qemu -net nic, -net bridge,br=br0 you are now ready to boot your qemu client with bridged network

[Ubutun] Repiar no sound problem on Ubuntu 16.04

Uninstall pulseaudio package

sudo apt-get purge pulseaudio

Remove the following files/folders

sudo rm -rf ~/.config/pulse /etc/pulse /usr/share/pulseaudio

Reboot you system

Reinstall pulseaudio package

sudo apt-get install pulseaudio

You might need to reinstall ubuntu-desktop if your 'Ubuntu System Settings' has disappeared

sudo apt-get install ubuntu-desktop

[gitlab] Backup & Restore

Backup Repository, Wiki, and etc.

sudo gitlab-rake gitlab:backup:create

Restore gitlab from a backup number 164486484 (move backup file under /var/opt/gitlab/backups/ folder)

sudo gitlab-rake gitlab:backup:restore BACKUP=164486484

Upload backup to local directory

Edit '/etc/gitlab/gitlab.rb', find 'backup_upload_connection', change 'local_root''s value with your backup path
----------------------------------------------------------------
gitlab_rails['backup_upload_connection'] = {
  'provider' => 'Local',
  'local_root' => '/mnt/backups'
}

# The directory inside the mounted folder to copy backups to
# Use '.' to store them in the root directory gitlab_rails['backup_upload_remote_directory'] = 'gitlab_backups' ----------------------------------------------------------------
Don't forget to give access permission for git user
You need to run gitlab reconfigure to apply new settings sudo gitlab-ctl reconfigure

Setup crontab for daily backup

sudo crontab -e Add the following two line command into your crontab (Ex. cron will execute gitlab backup every 2:00 A.M, and backup /etc/gitlab every 2:05 A.M) 0 2 * * * /opt/gitlab/bin/gitlab-rake gitlab:backup:create CRON=1 5 2 * * * umask 0077; tar -cf /mnt/gitlab/backups/$(date "+etc-gitlab-%s.tar") -C / etc/gitlab *if you get some error message which are related to folder permission, please make sure your backup location are writeable for git user.

Restore Configuration File (Move backup file under /etc/gitlab/ folder)

sudo tar -xf etc-gitlab-XXXXXXXXXX.tar -C /

Reference

https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/raketasks/backup_restore.md http://docs.gitlab.com/omnibus/settings/backups.html

[Ubuntu] Change network name to eth0

1. Modify GRUB_CMDLINE_LINUX="" with GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0" sudo nano /etc/default/grub 2. update grub and reboot sudo update-grub

Linux Subtitle Editor - (gaupol / gnome-subtitles)

gaupol sudo apt-get install gaupol gnome-subtitles sudo apt-get install gnome-subtitles