linux-misc.md

Resolving relative paths and symlinks

• If you need the absolute path of anything, including following symlinks to their actual file path, use readlink -f or realpath.
• If you just need the absolute path AND don't want to follow symlinks, use realpath -s

Finding which processes are accessing certain files

• fuser -fv FILE

/etc/issue file escape codes

- \b : Insert the baudrate of the current line.
- \d : Insert the current date.
- \s : Insert the system name, the name of the operating system.
- \l : Insert the name of the current tty line.
- \m : Insert the architecture identifier of the machine, eg. i486
- \n : Insert the nodename of the machine, also known as the hostname.
- \o : Insert the domainname of the machine.
- \r : Insert the release number of the OS, eg. 1.1.9.
- \t : Insert the current time.
- \u : Insert the number of current users logged in.
- \U : Insert the string “1 user” or “ users” where is the number of current users logged in.
- \v : Insert the version of the OS, eg. the build-date etc.

Virtual Console

Scrollback

• Shift+[PgUp,PgDown]

X Server

• xset q gives you lots of nice information about your current session's configuration.

Nice Figlet Fonts

• colossal
• future (!)
• speed
• computer
• emboss
• emboss2
• Merlin1
• ghost
• Merlin2
• coinstack
• larry3d
• chunky
• lean
• miniwi
• rebel
• alpha
• calvin s
• twisted
• univers

Randomly nice packages

• fzwal-git
• mgba
• snake-ncurses
• vixl44-git: pixel art :]

disk usage apps

• ncdu
• duf
• vizex

Mount .iso dvd image

• sudo mount -t iso9660 -o ro,loop .iso /mnt/iso

Grub

Interesting "ricing" kernel command-line options

        vt.color=       [VT] Default text color.
                        Format: 0xYX, X = foreground, Y = background.
                        Default: 0x07 = light gray on black.


        vt.default_blu= [VT]
                        Format: <blue0>,<blue1>,<blue2>,...,<blue15>
                        Change the default blue palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_grn= [VT]
                        Format: <green0>,<green1>,<green2>,...,<green15>
                        Change the default green palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_red= [VT]
                        Format: <red0>,<red1>,<red2>,...,<red15>
                        Change the default red palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_utf8=
                        [VT]
                        Format=<0|1>
                        Set system-wide default UTF-8 mode for all tty's.
                        Default is 1, i.e. UTF-8 mode is enabled for all
                        newly opened
        vt.cur_default= [VT] Default cursor shape.
                       Format: 0xCCBBAA, where AA, BB, and CC are the same as
                       the parameters of the <Esc>[?A;B;Cc escape sequence;
                       see VGA-softcursor.txt. Default: 2 = underline.

        vt.default_blu= [VT]
                        Format: <blue0>,<blue1>,<blue2>,...,<blue15>
                        Change the default blue palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_grn= [VT]
                        Format: <green0>,<green1>,<green2>,...,<green15>
                        Change the default green palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_red= [VT]
                        Format: <red0>,<red1>,<red2>,...,<red15>
                        Change the default red palette of the console.
                        This is a 16-member array composed of values
                        ranging from 0-255.

        vt.default_utf8=
                        [VT]
                        Format=<0|1>
                        Set system-wide default UTF-8 mode for all tty's.
                        Default is 1, i.e. UTF-8 mode is enabled for all
                        newly opened terminals.

        vt.global_cursor_default=
                        [VT]
                        Format=<-1|0|1>
                        Set system-wide default for whether a cursor
                        is shown on new VTs. Default is -1,
                        i.e. cursors will be created by default unless
                        overridden by individual drivers. 0 will hide
                        cursors, 1 will display them.

        vt.italic=      [VT] Default color for italic text; 0-15.
                        Default: 2 = green.

        vt.underline=   [VT] Default color for underlined text; 0-15.
                        Default: 3 = cyan.

Securely removing files

shred --remove FILE

Useful commands for memory and cpu usage

• used memory: free -h|awk '/^Mem:/ {print $3 "/" $2}'
• cpu consuming processes: ps axch -o cmd:18,%mem,pid --sort -%mem|head
• top configuration: zxcVm1t0W