Compose a statement for execution.

1x='echo $y'
2echo $x
3y=dragon
4eval "$x"

The results remain in the current shell, unlike sub-shells.

1b=basilisk
2sh -c 'echo $b'
3eval "g=goblin"
4echo $g

Find metadata.

1exiftool image.jpg

Find info on all images in current directory.

1exiftool -ext .png .

You can make this recurring with the -r switch.

And overwrite all metadata:

1exiftool -all= -overwrite_original -ext jpg .

(NB: This does not work on pdf data. See here for erasing all pdf data)

Or just GPS data:

1 …

Monitor all processes:

1extrace

Monitor one process:

1extrace ls

Monitor a script:

1./script.sh | extrace

SSH Daemon Jail

1sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.d/ssh.local

1[sshd]
2enabled = true
3
4ignoreip = 127.0.0.1/8 ::1,192.168.0.0/16 ::1

1sudo systemctl restart fail2ban

1sudo fail2ban-client status

1sudo fail2ban-client status sshd

Basics

Add your user to the audio group, and install festival-english.

1echo "(Parameter.set 'Audio_Method 'Audio_Command)" >> /usr/share/festival/voices.scm

1echo "(Parameter.set 'Audio_Command "aplay -q -c 1 -t raw -f s16 -r $SR $FILE")" /usr/share/festival/voices.scm

Set …

Basics

Translate a media file to a new type.

ffmpeg -i [input file] output_file.mkv

The input file might be a device, such as a camera.

#Record screen

Take the format as 'grab the x11 screen'.

1ffmpeg -f x11grab -s [screensize] -i :0.0 out.mkv

Get screensize with

1xrandr -q

or maybe just...

1ffmpeg -f x11grab -s " …

Basics

Update font-cache:

1fc-cache

List fonts:

1fc-list

Grab the part of the font name you need for Xresources:

1fc-list | cut -d: -f2

Add field 3 for styles.

Step 1: Multilib

Enable multilib (32-bit) support in /etc/pacman.d/mirrorlist:

1[multilib]
2Include = /etc/pacman.d/mirrorlist

And update:

1sudo pacman -Syu

Step 2: Check Card Manufacturer

Check your graphics card type:

1lspci  | grep VGA

Step 3: Install Drivers

Step 3A

If you see Nvidia, then install the intel …

Basics

The ordering of /etc/fstab is

1. disk
2. mount point
3. filesystem type
4. options
5. dump
6. pass

Example:

1UUID=877f14e8-4738-46b0-884f-ba330dad1a7d       /mnt/biggie                     ext4        nofail,rw,relatime      0 2
2
3UUID=B21648C416488AF5 /mnt/share ntfs …

Starting

New Machines

1git config --global user.email "$YOUR_EMAIL"

1git config --global user.name "$YOUR_NAME"

New Git

Start a git in directory $DIR:

1mkdir $DIR && cd $DIR

1git init

Make a file explaining what the project does:

1vim README.md

Add this to the git:

1git add README.md

Then make …