Shift + PgUp or PgDn will scroll through the console log.

Read    4
Write   2
Execute 1

• The ls command lists 7 metadata fields:

    <info> <hardlinks> <owner> <group> <size> <modified> <name>
  

  • info includes the file type (- for normal file, d for directory, p for named pipe, and l for symbolic link), and permission triples for owner, group, and others.

pacman -S <package_name>

pacman -Rs <package_name>

pacman -Syu
pacdiff

• You will need to install the pacman-contrib package to get pacdiff.
• If the kernel gets updated, don't forget to restart, otherwise you'll get weird errors.

• diff obtain and diff put are relative to the current split window, i.e. obtain copies from the other window to the current window and put copies from the current window to the other window.

• List of file and directory sizes in human-readable format:

    du -ah <directory>
  

• Total size of a directory:

    du -sh <directory>
  

• Start and stop:

    systemctl start <service_name>.service
    systemctl stop <service_name>.service
  

• Add and remove from boot sequence:

    systemctl enable <service_name>.service
    systemctl disable <service_name>.service
  

• Reload changed configuration files:

    systemctl daemon-reload
  

• See log of a given service:

    journalctl -u service-name.service -b
  

  • -b limits the log to the current boot session.

usermod -aG <group> <user>

groupadd <group>

uname -r

lsmod | grep <module_name>

• > writes to (i.e. overwrites) a file
• >> appends to a file

ssh -p port user@server-address

scp -P port <local/file> [email protected]:/remote/file

/connect chat.freenode.net
/msg NickServ idenfity marco1475 \<password\>
/join #archlinux

• Non-interactive consoles (most Linux-ones) source ~/.bashrc.

• Interactive consoles (e.g. macOS' Terminal) source ~/.bash_profile.

• To solve this problem make ~/.bash_profile source ~/.bashrc:

    if [ -f ~/.bashrc ]; then
        . ~/.bashrc;
    fi
  

dd if=/dev/urandom of=/dev/sdX bs=512

• Find out the bs value by running fdisk -l /dev/sdX and look for the "physical sector size".

• To check on the progress of dd, run the following command in a separate terminal:

    kill -USR1 $(pgrep dd)
  

• If /sys/block/md0/md/mismatch_cnt contains anything other than 0 you need to repair your RAID array.

• Instead of setting /sys/block/md0/md/sync_action to check, set it to repair:

    echo repair > /sys/block/md0/md/sync_action
  

  • You will have to do this as root, just sudo won't do.
  • You can monitor the repair (or check) progress by using cat /proc/mdstat.

• UUIDs:

    lsblk -no name,uuid
    ls -l /dev/disk/by-uuid/
  

• PARTUUIDs:

    lsblk -no name,partuuid
    ls -l /dev/disk/by-partuuid/
  

cryptsetup open --type luks /dev/sdaX <dev-mapper-name>
cryptsetup close <dev-mapper-name>

• The partition appears under /dev/mapper/<dev-mapper-name>

• systemd-boot assumes the EFI System Partition is mounted on /boot, which is not true in our case (it's on /esp and /boot is mount-bound to /boot).

• You have to pass --path to the update call:

    bootctl --path=/esp update
  

• The logs can be accessed through:

    journalctl -b
  

• Boot messages are cleared because:

  1. The kernel parameters at boot have the quiet flag set.
     • To fix this, remove the quiet flag from /esp/loader/entries/arch.conf's options line.
  2. Late KMS boot messages override the previous output.
     • There is no way to fix this.
  3. getty@tty1 service does not pass the --noclear flag to agetty.
     • Arch sets this flag by default.
  4. systemd clears the screen before showing the login prompt.

     • To fix this, create /etc/systemd/system/[email protected]/noclear.conf to override only TTYVTDisallocate for agetty on TTY1 and leave the global service file /usr/lib/systemd/system/[email protected] untouched.

         [Service]
         TTYVTDisallocate=no
       

1. Create a directory for the AUR build and change directories:

    mkdir ~/aur && cd ~/aur
   

2. Download the PKGBUILD tarball from the Arch User Repository:

    wget <url>
   

3. Extract the tarball to the AUR build directory created in step 1:

    tar -xvf <package_name>.tar.gz
   

4. Change directory to the extracted package, verify the PKGBUILD and all .install files for malicious code, and build the package:

    cd <package_name>
    makepkg -sri    # Run this as normal user, not root!