Category Archives: Command Line

Restore settings of Firefox on trouble

Update: 09-29-11 – Using script to automate process, see end of post.

When people have a issue with Firefox I’ve seen many people will resort to deleting their old profile (or folder) and creating a new one. This works but doing this will get rid of any passwords, history, bookmarks… therein. Having used Firefox quite a bit creating a new profile from time to time is a good idea anyhow as cruft, bad extensions, … can slow down browsing.


Copying the Firefox configs can be done by:

cd ~/.mozilla/firefox/

Backup the old profile and profile list:

mv xxxxxxxx.default{,.bck}
mv profiles.ini{,.bck}

Create a new profile:

firefox -CreateProfile <profilename>

This command will return the name of the new folder. Copy the basic settings to the new profile:

cd *.default.bck
cp places.sqlite key3.db cookies.sqlite mimeTypes.rdf formhistory.sqlite signons.sqlite permissions.sqlite webappsstore.sqlite persdict.dat content-prefs.sqlite ../*.<profilename>

This will transfer the bookmarks, browsing history, form entries, passwords, personal dictonary changes, and page zooms. There might be a couple other things wanted to add (possibly your firefox preferences), take a look at Transferring data to a new profile for more information.


Getting help when stuck in the console

If you’re in console (aka virtual console) doing an install or repairs on a system, it’s good to know how to get help if problems occur.

“Ground Control…”

To get help in console you can use a chat client. Read this page on how to set up irssi – a terminal/console IRC program. The guide will walk you through setting up irssi and connecting to freenode where many Linux distribution chat channels are located.

“Waiting for details, Houston…”

When you tell the people in the chat-room what your problem is, sometimes they will need to know additional information. This could be the output of a command or the contents of a configuration file. To do a command without leaving irssi do Ctrl+Alt+F2 (F3, F4… can also be used) to enter another console, then enter the command.

Be better not to have to write everything down on a notepad and then type it into irssi, this is where it becomes useful to use a collaborative debugging tool like pastebin. Pastebin is a website that temporarily holds configurations, bug outputs… that you can refer other people to get help. There are several tools that can be used from the command line that can send files to a pastebin service, for example pastebinit. Add pastebinit from your distro, then upload a file. For example, your xorg.conf file:

pastebinit /etc/X11/xorg.conf

For uploading the output of a command, first you have to put it into a file:

sudo fdisk -l &> partitions.txt

&> will redirect all output to a text file (both standard output and error output) and now it can be uploaded.

“I have visual…”

Occasionally you might need to actually show a picture of what your question is about (e.g. if you have a question about a console-based installer). For this you can use fbshot. fbshot is a framebuffer screenshot program. To take a screenshot of the first console (Ctrl+Alt+F1):

fbshot -c 1 console1.png

Then you can use a console web-browser and a image-hosting website to upload the image.

Customize man page colors with ‘less’ definitions

Man pages by default use less for displaying. I’ve used vim before to for colored text in man pages but something got bjorked in an update. To have color with man pages termcap will need to be invoked. Thanks to nico for the tip.

All that needs to be done is to export bold and underline values of termcap. Adding the values to the ~/.bashrc will make sure that they are always used:

# Less Colors for Man Pages
export LESS_TERMCAP_mb=$'\e[01;31m'       # begin blinking
export LESS_TERMCAP_md=$'\e[01;38;5;74m'  # begin bold
export LESS_TERMCAP_me=$'\e[0m'           # end mode
export LESS_TERMCAP_se=$'\e[0m'           # end standout-mode
export LESS_TERMCAP_so=$'\e[38;5;246m'    # begin standout-mode - info box
export LESS_TERMCAP_ue=$'\e[0m'           # end underline
export LESS_TERMCAP_us=$'\e[04;38;5;146m' # begin underline

And source the ~/.bashrc to have it work:

source ~/.bashrc

Some may notice I used Arch colors :) :

Updating BIOS with Linux

If you don’t have Windows installed and you need to upgrade your BIOS, Linux does have the tools to be able to create a BIOS flash CD. Not many companies make Linux flash utilities and alot of these utilites are DOS utilities so a bootable DOS disk is needed. This is a simple, easy way to create a BIOS flash CD.

First, get a BIOS image. You’ll need to download a BIOS image for your board. For information on what Flash utility to use, a good place to look is your computer manufacturers homepage. Award BIOS and American Megatrends BIOS are the most popular BIOS’s used on motherboards.

Editing FreeDOS Minimal Boot Image

Note: This didn’t work for me but plenty of people have had success with it, fdboot.img is a bit old and may not work on newer hardware. Look at flashrom below for another alternative.

FreeDOS provides a bootable DOS image. Download the DOS image to the Desktop:


and mount it:

sudo mount -t vfat -o loop /home/user/Desktop/fdboot.img /media/ISO

The BIOS flash utility and BIOS image will need to be added to the FreeDOS image. I prefer to use /media/ISO but any empty directory will do. The bootable image has a fixed size (1,440 Kb, the size of a floppy disk) and hence /media/ISO will also have that limited memory. The size needs to remain fixed in order to create a bootable floppy of it. You can see the space used in the image by:

du -b /media/ISO

Add the flash utility DOS executable and the BIOS image (there should be just enough room for it). I prefer to put these in a new directory but it’s up to you.

cd /media/ISO
mkdir bios
cp /home/user/Desktop/flashprog.exe /home/user/Desktop/bios-image /media/ISO/bios

The data added to the FreeDOS image will be saved when the ISO is unmounted:

sudo umount /media/ISO

Now return to the Desktop and convert the appended FreeDOS image to a bootable ISO:

mkisofs -r -b fdboot.img -c -o fdboot-bios.iso fdboot.img

The -b option defines the floppy image used for booting; the -c option will create a file that directs to fdboot.img and is necessary for booting; the -o option defines the output file, in this case a bootable iso; and finally the image file needs to be added.

Now burn the iso to the CD/DVD however you like. For example, from the command line:

cdrecord fdboot-bios.iso

Flash BIOS in Linux with Flashrom

Flashrom is a utility to directly flash the bios directly in Linux. It’s design to be a comprehensive utility and supports a good number of hardware devices. Above that, flashrom is easy to use. Check their page for compatibility, or install flashrom and see if it recognizes your chipset. I’d tell more but the flashrom website does a good job of telling about the utility.


Because BIOS sizes are getting larger, we may need to learn how to create larger bootable images. mkisofs mentions that is can create an El Torito (bootable) iso with either 1200 Kb, 1440 Kb, or 2880 Kb images. I know how to create an empty vfat image can be created with:

mkfs.msdos -C newimage.img 2880

And, of course, it can be mounted and the FreeDOS files can be copied there, but how could we make it bootable?


Color Output on Bash Scripts (Advanced)

I talked in a previous post about basic bash script colored output using the tput command. The tput command works for basic coloring (providing seven colors to choose from) but ANSI also provides a 256 color palette.

Note: Not all terminals support ANSI, but most do.

ANSI color coding is in this form:


The ANSI sequence: {ESC}[{attr};{bg};{256colors};{fg}m

{ESC} or \033 represents the ANSI escape-sequence. {attr} represents the outputs attributes (properties such as blinking and bold text), {fg} is the foreground color, {bg} is the background color, m means the sequence ends.

Note: The escape-sequence \033 works fine but at times you might have to use \e.

An example:

echo -e "My favorite color is \033[38;5;148mYellow-Green\033[39m"

The variable -e is required because echo doesn’t normally interpret backslashes and 033[39m tells bash to end the seqeunce. The 38 Value will use no background color. Notice too that I omitted the attribution value which if isn’t used will use the default (regular text) value.

To get color values a good program is colortest.

colortest -w

Colortest will show the ANSI color value to the corresponding hex value. Then just insert the ANSI value into the either the foreground or background value.
There’s also a program called conv-rgb2xterm that a hex value can be put in and it will give and ANSI sequence for the foreground color.


Color text output on bash scripts

Users who have been using Linux for awhile often learn that creating a basic script is a good way to run multiple, often-repeated commands. Adding a little color to scripts can additionally provide nice feedback. This can be done in a fairly straight-forward way by using the tput command.

A common way of doing this is to define the colors that tput can produce by putting them at the beginning of the bash script:

# scriptname - description of script

# Text color variables
txtund=$(tput sgr 0 1)          # Underline
txtbld=$(tput bold)             # Bold
bldred=${txtbld}$(tput setaf 1) #  red
bldblu=${txtbld}$(tput setaf 4) #  blue
bldwht=${txtbld}$(tput setaf 7) #  white
txtrst=$(tput sgr0)             # Reset
info=${bldwht}*${txtrst}        # Feedback

When writing new scripts using templates with these variables already defined can quicken the creation process and help keep scripts organized (my Bash Templates).

If just needing to use tput colors for specific instances this script can display the tput definitions and their corresponding possibilities:

# tputcolors

echo -e "$(tput bold) reg  bld  und   tput-command-colors$(tput sgr0)"

for i in $(seq 1 7); do
  echo " $(tput setaf $i)Text$(tput sgr0) $(tput bold)$(tput setaf $i)Text$(tput sgr0) $(tput sgr 0 1)$(tput setaf $i)Text$(tput sgr0)  \$(tput setaf $i)"

echo ' Bold            $(tput bold)'
echo ' Underline       $(tput sgr 0 1)'
echo ' Reset           $(tput sgr0)'

To use additional colors see: Color Output on Bash Scripts (Advanced).

Linux tidbits

Linux Tidbits

Regular commands I use every day in Linux plus a few eclectic ones. Basically geared to the new user. Tips or thoughts, please let me know.

Man pages

In Linux there is a manual for just about anything. Learn about almost everything by “man command” in the terminal. (e.g. man ls). Or type “command –help” for a basic description. Also, many man pages also cover configuration files (man resolv.conf).

Basic Commands


  • Up key– Command History
  • Tab – Auto-completion, nice and handy for completing file-names, directory names, and commands.
  • Commands are in this form: command -arguments

Files ( + directories )

  • ls ( list ), -l ( long ), -a ( shows hidden )
  • cp ( copy )
  • mv ( move or rename ), mv filename1 filename2
  • rm ( remove ) Very dangerous to use as root. Use with caution. -r ( recursive ) -f ( force – needed to remove a link)

Wildcards to expand definitions:

  • * (matches any character), cp *.txt ~/Desktop
  • ? (matches any single character), cp file?.txt ~/Desktop
  • [characters] (Matches a range/set of characters), cp [a-n]*.txt ~/Desktop</li>
  • [!characters] (Matches any character that is not a member of the set characters)


cd    #( change directory )
pwd   #( print working directory )
mkdir #( make directory )

A name followed by a / means it’s a directory, bash will figure it out if you don’t use it but some apps don’t. A safe syntax would be cd myfiles/

Command Output to Text (Standard Output)

ls /usr/bin > /home/user/Desktop/programs.txt

Add to an existing text file (append):

ls /sbin >> /home/user/Desktop/programs.txt

Pipes ( | )

Useful for using programs in conjunction with others:

ls -l | less


Popular filters used after piping:

  • sort – alpha-numeric ordering
  • uniq – removes duplicate lines of data
  • grep – returns the output of a specified pattern of characters
  • head, tail – outputs the first of last lines of output
  • tr – translates characters – can be used for upper/lower case conversion

Use grep to extract patterns from files

grep EE /var/log/Xorg.0.log
ls ~/Documents | grep recipe
glxinfo | grep -i direct

Files and File Permissions

View file permissions

List the files in “long” view:

ls -l

-rwxr--r-- 1 user user 225444 2007-05-01 21:58 abc.pdf
||  |  |     |    |
||  |  world |    group name
||  group    owner name
r = read = 4
w = write = 2
x = executable = 1

Change File Permissions

owner = rwx = 4+2+1 = 7; group = r = 4 ...

The above file’s permissions numerically is 744. To change permissions of the above file:

chmod 750 abc.pdf

Change Ownership

chown user:group /home/user/document.txt

Lazy way of make a file executable ;)

chmod +x ~/.scripts/example

File Systems

Show all partitions and their types:

sudo fdisk -l

Show mounted partitions used/available space:

df -h | grep ^/dev

See all file systems mounted::

cat /proc/mounts

Sort Directories by How much space they consume:

du | sort -nr

Define Disks and Partitions and how they mount

sudo mkdir /mnt/USB-Drive
sudo mount -t vfat -o rw /mnt/USB-Drive

types include hfsplus, vfat…

The fstab file defines how to mount available disks/partitions that can automatically be mounted it at boot: Enter in /etc/fstab:

/dev/sda2    /mnt/OSX          hfsplus ro,exec,auto,users    0      0
/dev/sda4    /mnt/Shared_Disk  vfat users,auto,uid=1000,gid=100,umask=007  0 0

ro – read-only, rw – read-write, auto mounts filesystem on boot

If the disk will resemble another disk it is better to use a unique device ID (UUID) rather than /dev/disk:

sudo blkid /dev/disk

Unmount all possible file systems:

umount -a

File System Check

Only filesystems that are able to be unmounted can have the filesystem checked.

Reboot immediately and check for errors:

sudo shutdown -Fr now

For specific mounted filesystems they can be check on next boot by placing a forcefsck file at the root of the disk/partition:

sudo touch /forcefsck
sudo touch /home/forcefsck

This will not run a file system check though if the file system is marked clean. For this boot a rescue disk and run fsck -f to do this.

Change how often fsck runs at boot (-c = count boots, -i = time interval):

sudo tune2fs -c 30 -i 6m /dev/disk

Check and mark bad blocks on damaged drives:

fsck -vcck /dev/disk

Mounted file systems should be checked from the Installer CD/DVD or on boot.


Create swapfile

dd if=/dev/zero of=/swapfile bs=1024 count=2097152

Swap is recommended to be 1-1/2 to 2x the value of the RAM to use for hibernation.

1 GB = 1024 MB = 1024 x 1024 kB = 1048576 kB = 1048576 kB x 1024 bytes/kB = 1,073,741,800 bytes10
mkswap /swapfile
swapon /swapfile

Add to /etc/fstab:

/swapfile              swap             none     defaults

Controlling Swap

Turn off swap:

swapoff -a /swapfile

Swapiness is the input/output priority of swap. To measure the current value:

cat /proc/sys/vm/swappiness

To change the swap priority (higher value means more swapping):

sudo sysctl vm.swappiness=10

to use this value permanently add it to /etc/sysctl.conf (vm.swappiness=0). Values of 20 or lower are better for laptops.

File Compression


tar gunzip:
tar cvpzf /AreaToSaveTo/yourcompressedfile.tgz --exclude=/this/folderorfile /CompressionStarts/Here
tar.bz2(tbz2) (block sorted, better compression):
tar -cvjf files.tar.bz2 fileorfolder
bzcat linux-2.6.XX.tar.bz2 | tar x


tar xvf file.tgz
unrar e file.part01.rar

Span Multiple Volumes


tar -c -M --tape-length=2294900 --file=part1.tar too-large-archive.tgz


tar -x -M --file=part1.tar too-large-archive.tgz

At prompt specify new (n),
then specify volume name (e.g. n part2.tar)
tape-length is 1024 bytes measurement or (1 computer kilo)

Or use “split” to break a large volume (2m = 2 megabytes, LF is the prefix for new name):

split -b 2m largefile LF_
tar -cvj /full/path/to/mybigfile | split -b 650m

Put back together:

cat file* > newfile

Backup and Restore

Tar – From Install CD

cd /mnt/distro
tar -czpvf /mnt/distro/macbook_distro_date.tgz *

Rsync – Full Backup

rsync -avtp --delete --exclude=/home/user/somedir /source/dir /destination/dir
  • -a archive, -v verbose
  • -t preserve modification times, -p permissions
  • --delete removes destination file if has been removed from source
  • --links recreate symlinks
  • -z compress from source to destination – good for slow connections.
  • use “-a e ssh source name@hostname:dest” for ssh


Add user

useradd -m -G adm,audio,cdrom,cdrw,cron,games,plugdev,portage,shutdown,usb,users,video,wheel -s /bin/bash user

Groups may vary some per distribution. Some groups will not be available until a certain program is installed.

Add/delete user to group:

gpasswd -a user plugdev
gpasswd -d user plugdev

See what groups user belongs to:


Remove user:

userdel username


Writing to CD/DVD with Rock-Ridge support

Rock-ridge support add Unix file extensions and attributes for iso9660 standard disks.
DVD are marked as 4.7GB capacity but thats just the marketing measure. In terms the computer understand the space on a DVD is 4.368 GB’s (1 GB = 1048576 kB x 1024 bytes/kB). DVD +R at 4x or 8x for best performance


growisofs -Z -lrJ -joliet-long /path/to/files
  • -Z means to start at the beginning of the dvd
  • l allows long filenames (breaks DOS compatability)
  • r Rock-ridge support
  • -J Add Joiliet support
  • -joliet-long – allows Joliet filenames to be 103 characters long instead of 64 – breaks joliet compatibility but works in most cases.


mkisofs -o my.iso -lrJ /path/to/files

Then burn iso to CD (not sure if I can write directly to CD, from what I’ve seen it would seem that I can’t).

Blanking a Disk
If you want to blank a disk or it already has a file-system on it you’ll see an error like “WARNING /dev/hda already carries isofs!” then reinitialize the filesystem:


dvd+rw-format -f /dev/sr0
growisofs -Z /dev/hda=/dev/zero


cdrecord -v dev=/dev/hda blank=fast
cdrecord -v dev=/dev/hda speed=2 blank=fast
cdrecord -vv dev=1,0 blank=all


Write ISO to CD/Drive:

dd if=name.iso of=/dev/sdb1

Mount ISO:

mount -t iso9660 -o loop,ro name.iso

Create an ISO from a DVD or CD:

dd if=/dev/sr0 of=name.iso

Create and ISO from a file/directory:

mkisofs -o name.iso /path/to/file_or_directory

CDRWin (.bin/.cue) images to ISO:

bchunk name.bin name.cue name.iso
bin2iso name.cue

Converting CloneCD images to ISO:

ccd2iso name.img name.iso

Converting nrg (Nero) images to ISO:

nrg2iso name.nrg name.iso

Support for writting large file sizes

ISO has file size limit of 4GB (untested -udf support is still in alpha):

mkisofs -o my.iso -lrJ -allow-limited-size -udf file-or-pathtofiles
growisofo -Z /dev/sr0 -lrJ -allow-limited-size -udf file-or-pathtofiles


Change keymaps:

setxkbmap dvorak

Map pointer buttons to keyboard:

xmodmap -e 'keycode 116 = Pointer_Button2'
xmodmap -e 'keycode 108 = Pointer_Button3' 
xkbset exp m

Hardware Info

Kernel messages about hardware

dmesg | less

Cpu info:

cat /proc/cpuinfo

List all PCI/USB devices


Detect hardware as it’s plugged in

sudo tail -f /var/log/messages

lshal –monitor # more detail

Icons / Cursors / Fonts …

Reset Icon Cache

gtk-update-icon-cache -f /usr/share/icons/hicolor/

Convert Windows Icons to Linux

broken ink

Reset cache for fonts:

fc-cache -vf

Build font info per directory:


Take screenshot of selected area

import filename.png

Set gamma

If you have ability to calibrate your own icc profile (Macintosh’s do) copy the icc profile to Linux and use “xcalib icc.profile“, otherwise a basic gamma can be set:

xgamma -bgamma 0.925 -ggamma 0.925 -rgamma 0.925


Shutdown at a specific time

shutdown -h 22:33
shutdown -P now


Use “date” to check date and to set system clock:

date MonthDayHourMinuteYear

Find out kernel version:

uname -r

Start Program that isn’t in the Systems Path

Only programs that are in a system’s $PATH setting can be started by typing the command, otherwise:


Disable Touchpad whilest Typing

syndaemon -d -t -i 2



Change or add password to smbconf:

sudo smbpasswd -L -a user

Mount SMB share to folder:

sudo smbmount // mnt/directory -o username=username,password=pass,uid=1000,mask=000

Mount all Samba Shares in fstab:

mount -a -t smbfs


SSH Howto

Remote login with SSH with username (diferent than the one you’re using):

ssh -l username

Copy remote file to local file:

scp -p user@

Download entire website:

wget -r



The Bash configuration file (~/.bashrc) file:

Adding PATHs to the ~/.bashrc file will make the system aware of another folder that has executables and shortcuts can be created for common commands:

export PATH=$PATH:/home/user/.scripts:
alias capscreen="import ~/Desktop/screen.png"

To see the preset variables already defined for bash:


Search History


Cron is the system program scheduler. It checks every minute for commands to run. To edit a crontab (cron jobs):

crontab -e

#   minute (0-59),
#   |   hour (0-23),
#   |   |   day of the month (1-31),
#   |   |   |   month of the year (1-12),
#   |   |   |   |   day of the week (0-6 with 0=Sunday).
#   |   |   |   |   |   user

43 08 * * * env DISPLAY=:0.0 audacious /home/user/My\ Music/Other/Alarms/301gq.mp3

chroot – (changing root)
Userful for logging into your current Linux from an installtion CD:

mkdir /mnt/osname
mount /dev/sda3 /mnt/osname
mount -t proc none /mnt/osname/proc
mount -o bind /dev /mnt/osname/dev
chroot /mnt/osname /bin/bash

Compile Kernel

make oldconfig
make menuconfig
make clean zImage modules modules_install install

For PPC “make pmac32_defconfig” will generate a basic config.

Find Kernel Modules:

find /lib/modules/*Kernel-Version* -type f -iname '*.o*' -or -iname '*.ko*'

Add the screen program to be able to background a terminal process
screen command (CTRL + A + D to background it, to return it: screen -r).

Use noup to continue a process even if you log out

noup command

Unsorted/Less Used

sudo echo >> no work

echo "my text" | sudo tee /etc/portage/package.use

See whats taking up ram:

ps auxf --sort size

Allow window executables to run directly (will need Wine and misc. binaries enabled in kernel)

In /etc/sysctl.conf add:

fs.binfmt_misc.register = :WINEXE:M::MZ::/usr/bin/wine:

and add to fstab:

none /proc/sys/fs/binfmt_misc  binfmt_misc  defaults 0 0

Re-size Images from the command line

Requires imagemagick to be installed (convert writes new image, mogrify overwrites):

convert image.jpg --resize 800x600 newresized.png
mogrify -geometry 1024x768 *.png

Copy ALL Files (+invisible, hard links, softlinks)

find . -depth -print0 | cpio -null -sparse -pvd /mnt/newhome/

Create random numbers, hex letters

dd if=/dev/random bs=1 count=5 2>/dev/null | xxd -ps

Run programs sequentially or concurrently

program1 && program2
program1 & program2

A simple web server

Share files in directory and all subfolders:

python -c "import SimpleHTTPServer;SimpleHTTPServer.test()"

View at http://localhost:8000 or http://your_ip:8000/.

Debian Specific:

drive space show taken by installed packages

dpkg-query -W --showformat='${Installed-Size;10}\t${Package}\n' | sort -k1,1n

Rebuild Font Directory

dpkg-reconfigure fontconfig