====== How-tos (Some useful Linux tips) ======

===== Multimedias - Conversions =====

==== Convert Wav to Flac ====
Convert all wav files to flac files in a folder

<code bash>
for i in *.wav; do ffmpeg -i "$i" "$i".flac ; done
</code>

==== Convert Wav to Mp3 ====

<code bash>
for i in *.wav; do ffmpeg -i "$i" -acodec mp3 -ab 320k "$i".mp3 ; done
</code>
==== Convert to 16 bits Flac ====
<code bash>


for i in *.flac; do ffmpeg -i "$i" -af aresample=dither_method=triangular -sample_fmt s16 -ar 44100 "$i".flac ; done



</code>
==== Convert Flac to Mp3 files ====

<code bash>
for f in *.flac; do flac -cd "$f" | lame -b 320 - "${f%.*}".mp3; done
</code>



==== Compress all mp4 videos in a folder ====
<code bash>
for i in *.mp4; do ffmpeg -i "$i" -vcodec libx265 -crf 28 "${i%.*}_compressed.mp4"; done
</code>

==== Compress all mov videos in a folder ====

<code bash>
for i in *.mov; do ffmpeg -i "$i" -vcodec libx265 -crf 28 "${i%.*}_compressed.mp4"; done
</code>
==== Convert HEIC images to jpg ====
<code bash>
sudo apt install libheif-examples
for file in *.heic; do heif-convert "$file" "${file/%.heic/.jpg}"; done
</code>
==== Pick a random file with Totem ====
<code bash>
totem "$(ls -R | shuf -n1)"
</code>

==== Compress PDF files ====

<code bash>
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook \
    -dNOPAUSE -dQUIET -dBATCH -dDetectDuplicateImages \
    -dCompressFonts=true -r150 -sOutputFile=output.pdf input.pdf
</code>

Summary of -dPDFSETTINGS:

  * ''dPDFSETTINGS=/screen'' lower quality, smaller size. (72 dpi)
  * ''dPDFSETTINGS=/ebook'' for better quality, but slightly larger pdfs. (150 dpi)
  * ''dPDFSETTINGS=/prepress'' output similar to Acrobat Distiller "Prepress Optimized" setting (300 dpi)
  * ''dPDFSETTINGS=/printer'' selects output similar to the Acrobat Distiller "Print Optimized" setting (300 dpi)
  * ''dPDFSETTINGS=/default'' selects output intended to be useful across a wide variety of uses, possibly at the expense of a larger output file

==== If Totem can't read some mkv or mp4 vidéo ==== 
After upgrading to Ubuntu 22.04 I had some issue to read some video files (Totem crash at startup, display the error "The specified movie could not be found" or open the video with a strange format. 
I did install the Intel non-free drivers to solve this issue:
<code bash>
sudo apt install intel-media-va-driver-non-free ubuntu-restricted-extras
</code>

===== Files =====
==== Remove files recursively ====

<code bash>
# remove lrc files
find -type f -name "*.lrc" -delete
# remove .DS_Store files
find -type f -name ".DS_Store" -delete
</code>

==== Remove duplicate files ====

<code bash>
fdupes -rdN .
</code>

==== Uncompress .tar.gz file ====
<code bash>
tar -zxvf file.tar.gz
</code>

==== Uncompress .tar.bz2 file ====
<code bash>
tar -xvjf file.tar.bz2 
</code>


==== Remove empty folders ====
<code bash>
find . -type d -delete
</code>

==== Search .Mp3 files ====
<code bash>
find . -iname "*.mp3" -print
</code>

===== Network =====

==== Download test ====
<code bash>
curl -4 -o /dev/null http://bouygues.testdebit.info/100M.iso
</code>

==== Upload test ====
<code bash>
curl -o /tmp/temp.iso https://bouygues.testdebit.info/100M.iso
curl -4 -o /dev/null -F "filecontent=@/tmp/temp.iso" http://bouygues.testdebit.info
</code>

==== Display public IP address ====
<code bash>
host myip.opendns.com resolver1.opendns.com
</code>

==== Open ports connexions ====

<code bash>
sudo netstat -antp
</code>


==== Connected users list ====
<code bash>
who
</code>

==== Disconnect a user ====
<code bash>
sudo slay user_name
</code>

==== Firewall - Status ====

<code bash>
sudo ufw status verbose
</code>

==== Trafic - bandwidth utilisation ====


<code bash>
sudo iftop -i enp9s0
</code>

==== SSH - Launch X application over SSH ====
<code bash>
ssh user@host -XC application
</code>

==== FTP - Add user ====
<code bash>
ftpasswd --passwd --name=bob --uid=1001 --home=/home/bob --shell=/bin/false
</code>


==== NcFTP - connection ====

<code bash>
ncftp -u username -p apssword ftp://ftpperso.free.fr/dir/
</code>

==== NcFTP - folder copy ====

<code bash>
sudo ncftpput -R -u username ftpperso.free.fr / /dir_to_copy/*
</code>

===== Hardware  =====

==== Component list ====

<code bash>
sudo lshw | more
</code>

==== Getting SMBIOS data from sysfs==== 

<code bash>
sudo dmidecode
</code>

==== CPU information ==== 
<code bash>
sudo lscpu
</code>

==== Battery information ====

<code bash>
upower -i /org/freedesktop/UPower/devices/battery_BAT0
</code>


==== Check Wifi signal ====
<code bash>
wavemon
</code>
===== System =====

==== Monitor ====

<code bash>
sudo glances --enable-plugin sensors
</code>


==== CPU frequency ====
<code bash>
cpufreq-info
</code>


====  CPU Over temperatures Log occurrences ====

<code bash>
sudo journalctl --since "2023-01-01" | grep temperature
</code>


==== Power Usage ====

<code bash>
sudo powertop
</code>

==== Security: detect signs of rootkits====

<code bash>
sudo chkrootkit
</code>
===== Hard-drive =====

==== Folders/files usage ====
<code bash>
sudo gt5
</code>


==== Disk - Free space on /boot partition ====

<code bash>
//check current kernel
uname -r
//check if list of old kernels is correct 
dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e '[0-9]'
//purge old kernels
dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e '[0-9]' | xargs sudo apt-get -y purge
</code>

==== SMART information ==== 
<code bash>
sudo smartctl -A /dev/sda
</code>

==== Set HD to low power consumption standby mode ====
<code bash>
sudo hdparm -y /dev/sdb
</code>

==== Hard drive current state ====

<code bash>
sudo hdparm -C /dev/sdb
</code>

==== Hard drive current Advanced Power Management (APM) value ====

<code bash>
sudo hdparm -B /dev/sdb

</code>

==== Change APM value  ====
60 = 5x60 = (5 minutes)
<code bash>
sudo hdparm -B60 /dev/sdb
</code>

===== Fstab =====
Install cifs/nfs
<code>
sudo apt install nfs-common
sudo apt install cifs-utils
</code>



===== Install DCP-7055W scan driver =====

<code bash>
brsaneconfig4 -a name=(name your device) model=(model name) ip=xx.xx.xx.xx
</code>

https://support.brother.com/g/b/downloadhowto.aspx?c=us_ot&lang=en&prod=dcp7055w_us_eu_as&os=128&dlid=dlf006645_000&flang=4&type3=566



===== Fail2ban =====

Get SSH banned IP
<code bash>
fail2ban-client status sshd
</code>

===== Nginx ===== 
==== GoAccess - Log statistics (terminal) ====

  * Live statistics
<code bash>
tail -f access.log | goaccess -
</code>

  * Using single log file
<code bash>
goaccess access.log
</code>

  * Using all log files (including .gz files) 
<code bash>
zcat -f access.log* | goaccess -
</code>

  * Date ranges
<code bash>
sed -n '/'$(date '+%d\/%b\/%Y' -d 'last week')'/,$ p' access.log | goaccess -a -
sed -n '/'$(date '+%d\/%b\/%Y' -d 'last month')'/,$ p' access.log | goaccess -a - 
sed -n '/'$(date '+%d\/%b\/%Y' -d '1 month ago')'/,$ p' access.log | goaccess -a - 
sed -n '/'$(date '+%d\/%b\/%Y' -d '1 week ago')'/,$ p' access.log | goaccess -a - 
sed -n '/'$(date '+%d\/%b\/%Y' -d 'yesterday')'/,$ p' access.log | goaccess -a - 
sed -n '/'$(date '+%d\/%b\/%Y' -d 'today')'/,$ p' access.log | goaccess -a -
</code>
==== GoAccess - Log statistics (dynamic HTML page) ==== 
<code bash>
goaccess access.log -o /var/www/html/report.html --log-format=COMBINED --real-time-html
</code>
==== Count pages sorted by response code ====

<code bash>
awk '{print $9}' access.log | sort | uniq -c | sort -rn

</code>
==== Count 404 respond code ====

<code bash>

cd /var/log/nginx/
awk '($9 ~ /404/)' access.log | awk '{print $7}' | sort | uniq -c | sort -rn


</code>

==== Hotlink ====

<code bash>
awk -F\" '($2 ~ /\.(jpg|gif)/ && $4 !~ /^https:\/\/eolienne\.f4jr\.org/){print $4}' access.log | sort | uniq -c | sort
</code>



==== List of 20 most connected IP address (since a date) ====

<code bash>
awk '/Jan\/2024/ {print $1};' access.log | sort | uniq -c | sort -rn | head -20
</code>

==== Top 10 IP address sort by bandwidth utilization ====

<code bash>
awk 'BEGIN{ PROCINFO["sorted_in"]="@val_num_desc" }
     { a[$1]++; b[$1]+=$10 }
     END{ 
         for(i in a) { if(++c>10) break; printf "IP: %s: ",i ; system(sprintf("numfmt --to=iec-i %s",b[i])) ; } 
     }' access.log
</code>
===== MySQL =====

==== Secure  ====

<code bash>
sudo /usr/bin/mysql_secure_installation
</code>

==== Create backup user ====

<code bash>
sudo mysql -uroot -p
GRANT LOCK TABLES, SELECT, RELOAD ON *.* TO 'backup'@'localhost' IDENTIFIED BY 'PASSWORD';
</code>

==== Password for backup ====
<code bash>
/etc/mysql/conf.d/mysqldump.cnf
</code>

==== Create database ====

<code bash>
mysql -p -u root

CREATE DATABASE db_name;

GRANT ALL PRIVILEGES ON db_name.* TO 'db_user'@'localhost'
IDENTIFIED BY 'password' WITH GRANT OPTION;
</code>

==== Connect to database ====
<code bash>
mysql -p -u root -D db_name
</code>

==== Show tables ====
<code bash>
SHOW TABLES ;
</code>






===== AirPlay =====

==== Pulse Audio ====

Installation of Airplay in Ubuntu 22.04 with Pulse Audio

  * https://bugs.launchpad.net/ubuntu/+source/paprefs/+bug/1871899?comments=all
<code bash>
# Airplay ability 
sudo apt install pulseaudio build-essential paprefs git pulseaudio-module-raop intltool libjack0 pavucontrol pulseaudio-module-zeroconf

#bug pulseaudio 
sudo ln -s /usr/lib/pulse-16.1+dfsg1/ /usr/lib/pulse-16.1
pactl load-module module-raop-discover
</code>

==== PipeWire ====

Discover Airplay in Ubuntu 22.10 with PipeWire

<code bash>
sudo vi /etc/pipewire/pipewire.conf
</code>
Add the following line to load module inside the //context.modules = [// section

<code bash>
{ name = libpipewire-module-raop-discover }
</code>


==== HandBrake ====


<code bash>
sudo apt install libdvdnav4 libdvdread4 gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly libdvd-pkg
sudo dpkg-reconfigure libdvd-pkg
sudo apt install ubuntu-restricted-extras
</code>
 
===== Pi-hole =====


==== Upgrade ====
<code bash>
pihole -up
</code>



===== Gnome =====

Move the Dock 'Show Applications' button at top
<code bash>
gsettings set org.gnome.shell.extensions.dash-to-dock show-apps-at-top true
</code>

Move the windows control button to the left

<code bash>
gsettings set  org.gnome.desktop.wm.preferences button-layout 'close,minimize,maximize:'
</code>

===== Synology =====

==== Edit Synology IP Block list ====

Remove an IP address in case your IP address has been blocked by DSM firewall (Error message "IP Address blocked due to too many failed login attempts") 

Login to your NAS using SSH with an admin group account 
<code bash>
ssh user@192.168.x.x -p port_number
</code>

Once connected, get the root rights entering your password 

<code bash>
sudo -i
</code>  

Now remove the blocker IP address from the database  

<code bash>
cd /etc
sqlite3 synoautoblock.db
sqlite> delete from AutoBlockIP where IP ="x.x.x.x";
</code>
===== Nice projects =====
  * Raspberry Pi : https://www.raspberrypi.org/ - Tiny computer 
  * Pi-Hole : https://pi-hole.net - Ad blocking using DNS - With [[https://github.com/pi-hole/pi-hole/wiki/DNSCrypt-2.0|DNSCrypt-Proxy]] 
  * Firefox : https://www.mozilla.org/en-US/firefox/new/ - The Web Browser 
  * Bitwarden : https://bitwarden.com/open-source/ - Password manager
  * MoodeAudio : http://www.moodeaudio.org/ - Audiophile-quality music playback
  * HifiBerry : https://www.hifiberry.com/ - Audio additional boards for Rpi
  * OpenHAB : https://www.openhab.org/ - Smart Home
  * Home Assistant : https://www.home-assistant.io/ - Open source home automation
  * DD-WRT : https://dd-wrt.com/ - Free your router 
  * Ubuntu : https://ubuntu.com/ - Linux distribution 
  * Shelly : https://www.shelly.com/en-fr - Smart Home Automation
  * Nicotine+ : https://nicotine-plus.org/ - Soulseek is not dead
  * Kodi : https://kodi.tv/ - Media Centre  
  * NGINX : https://www.nginx.com/ - Web Server
  * Amplify : https://amplify.nginx.com - Web Server Monitoring
  * VideoLAN : https://www.videolan.org/ - Powerful media player 
  * Waze : https://www.waze.com/ - GPS