Category Archives: Command Line

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/gentoo
tar -czpvf /mnt/gentoo/MacBook-Gentoo-Backup.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, this one is for Gentoo. 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


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

Gentoo Linux Tidbits

I’ve been using Gentoo for about two years now and I took notes on managing my box. These are those notes. If you’re interested in installing Gentoo take a look at Gentoo Quick Install.

Update: bash script

This section is an addition. I’ve since created a bash script that does many of the functions and make reading the rest less necessary. The script is self-explanatory: link.

About Portage

Gentoo Linux uses a package management system called Portage. Portage offers one of the most extensible and customizable package systems available in Linux.

System Update

Update all packages on the computer. This process involves: syncing Portage, creating a text file to review updates, updating the system, merging new configuration files, remove orphaned dependencies.

Sync the portage tree

emerge --sync # or
eix-sync      # preferrable for faster searches (eix search)

Examine update before install

emerge --pretend --verbose --update --newuse --deep @world | less

If unexpected dependencies are being pull in, use the --tree option to track it down.

Complete update

emerge --update --newuse --deep --with-bdeps=y @world
revdep-rebuild  # ...
emerge --depclean
  • In the first command, portage wiil update all packages on the system
  • dispatch-conf is configuration updating and merge tool
  • revdep-rebuild will check that all programs and libraries are linked correctly and rebuild them if necessary.
  • emerge --depclean will remove orphaned dependencies
  • Additionaly a kernel update may need compiling again, distfiles may need to be cleaned up…

Failed package emerge in compilation string

At times in a long list of package emerges (like a system update) a package will fail to emerge. The bug-tracker and the forums usually have information about known problems with the package. If not, it’s possible the package needs a newer version of a package that has not yet been installed in the compilation string. Skipping the problem package and emerging it again when the rest of the packages are compiled may fix the problem.

emerge --resume --skipfirst

Blocked packages

Packages that block other packages from being emerged can be fixed by removing the obstructing packages then reinstalling it after blocked package is emerged.

quickpkg $BLOCKER
emerge -C $BLOCKER
emerge $BLOCKED
emerge --usepkgonly $BLOCKER

Specify USE Flags per package

In /etc/portage/package.use add pkg-category/pkg useflag useflag2. To add a USE flag temporarily (not recommended):

USE="useflag" emerge package

Masked Packages (keyword)

The “missing keyword” mask states an ebuild doesn’t support or hasn’t been tested on the current architecture (x86, amd, ppc… ). Keywording can be added to /etc/portage/package.accept_keywords for example: media-libs/libquicktime ~ppc.

Masked Packages (hard)

Gentoo hards masks some packages for security concerns, collisions… Packages are hard masked in /usr/portage/profiles/package.mask. If liking to live on the edge packages can be unmasked in /etc/portage/package.unmask.

Emerge dependency of a package

Packages that are dependencies of other packages (i.e. have no use on their own) should be emerged as oneshot. This is because if the main package is removed so too will this package when emerge –depclean is run. Otherwise these dependent packages are added to the world file.

emerge --oneshot package

Freeze a Package

If a rebuild of a package is undesired a package can be frozen. This is useful for kernels and other such packages.

  • Mask the entire package (i.e. without version) in /etc/portage/package.mask with sys-kernel/gentoo-sources.
  • Add the specific version to /etc/portage/package.unmask with sys-kernel/gentoo-sources-version.

Create a Binary Package

If enough disk space is available its may be a good idea to create and archived-binary of a package so it is quicker to re-install:

emerge --buildpkg zim
emerge --usepkg zim    # to reinstall

Info About the Portage System

This information can be useful for reporting bugs:

emerge --info

Other Portage Tools

Info about USE flags (equery is part of gentoolkit):

equery uses package

Programs built with a specific USE flag:

equery hasuse useflag

View what files are installed by program:

equery files alsa-lib

View what packages install to a folder:

equery belongs /usr/share/fonts/misc

List all installed packages:

equery list

Select a new system profile (With each new revision (i.e. 2006.1 to 2007) new profiles are added. Profiles define basic system USE flags…):

eselect profile list
eselect profile set 4

Select new kernel:

eselect kernel list
eselect kernel set 2

Rebuild external modules (added from Portage). Drivers build against the kernel (video drivers, sound drivers…) and will need to be rebuilt with new kernels:

emerge --ask @module-rebuild

Compile with specific compiler version. Some packages require a specific version of the compiler. See installed GCC profiles and select one:

gcc-config -l
gcc-config 2
source /etc/profile

Clean portage world file:

Remove entries that are dependencies only in /var/lib/portage/world to help emerge times. Careful what to remove thought. For example, “epiphany-extensions” requires “epiphany” so if “epiphany” is removed and later its decided that “epiphany-extensions” are no longer needed than running `emerge –depclean’ will removed “epiphany”.

Layman / Overlays

Overlays are package repositories that can be added to the portage tree. A good number of third party overlays are available in necessary.

Local Overlay

Create a local overlay to create your own ebuilds or edit an existing one. If the later, it’s best to see if the program has an ebuild in bugzilla or is in one of the third party overlays.

To make a personal overlay create an overlay directory and let make.conf known to it (for example) mkdir /home/user/.portage-local and add to make.conf:


Ebuilds must be placed in a category that already exists in Portage

mv package.ebuild ~/.portage-local/media-plugins/

Keyword if necessary:

emerge gentoolkit-dev
ekeyword ~ppc package-

Create a manifest and build:

ebuild ~/.portage-local/category/program/program-version.ebuild digest
emerge package


Layman is a manager for third party overlays.

emerge layman subversion

Add to make.conf:

source source /var/lib/layman/make.conf

To add an overlay:

layman --list
layman --add overlay

Update layman overlays:

layman -S

Creating Quality Web Sized PNGs with ImageMagick

Note: This is a post with me messing around with ImageMagick and it’s good food for thought, however as a reader pointed out I accidentally started with a lossy image and turned it to a lossless image which was a mistake on my part.

I recently posted The Battle for Wesnoth – 1.4 picture review, a look at the new version of turn based strategy game. I had uploaded the post and the screenshots from a super fast pc at work. I gave it no thought when it was as easy as clicking a button. No thought until I loaded the blog at home yesterday and I patiently waited as the browser icon kept looping. Scrolling to the Wesnoth post and seeing images were only half loaded, I looked into my images folder and discovered my Wesnoth screenshots took up a whooping 4MB. Yikes! To make matters worse, I had lazily used html image resizing for thumbnails. This was a time warp I’d forgotten with fast networking but a basic html blunder: when writing for a general audience, write for the lowest common denominator. Scrolling my other posts and their images were still loading I thought, if I had visited this page for the first time and it was taking this long to load, I probably would have closed the tab by now.

And such it is on todays modern web. Not everyone has that T3 spliced into their home. On this slow connection, I have learned to be patient but I really like those pages that load quickly. Portable Network Graphics (PNG)’s the graphic format I use are designed for modern networks. A lossless format for good quality images with a reasonable file size for optic networks, cable modems and dsl. A good number of people though still use standard phone modems or experience congested networks and some images can take awhile to download. Well compressed PNG’s can be made though that load reasonably well while maintaining good image quality.

So I decided to find out what I could do to reduce the load of my web graphics. I did numerous tests over differing quality and quantity. I tested all conversions from a standard jpeg photo. The image is scaled down to 500 width (aspect preserved), a good size for viewing on this blog. First of all I have to say that GIMP does this very well – accurate color reproduction, smoothing, no color bleeds, all in a 270K file.

But often I don’t wanna fire up gimp just to convert one image in such instance I like to use ImageMagick’s command line programs: convert/mogrify.

Resizing is simple:

convert -resize 500 a-friend-in-need.jpg a-friend-in-need-500.png

The image produced is as good as quality as the one produced by GIMP but doesn’t particularly do well at compression this image is a whopping 871K which explains alot about my web page load yesterday. So next I reduced the colorspace to 256 to see if this could produce an acceptable image:

Not too bad. At 109K its a good size for the internet but after looking awhile the dithering becomes obvious. The number of colors is a big factor in determining the size of the image. I played with the colors a bit and came to that around 2000 colors as images began to look non-dithered.

convert -resize 500 -colors 2048 -depth 16 -quality 95 a-friend-in-need.jpg a-friend-in-need-500-c256.png

Quality is the compression amount and type. The first digit is the compression level (nine is the highest) and the next digit is compression type (five is adaptive). I also used optipng that can add up to 30% further compression.

optipng -o5 a-friend-in-need-500-c256.png

The images still look a bit too sharp so I used the enhance variable to smooth. Enhance is it’s own filter and will over-rule other variables so setting color and depth needs to be done in another step.

Doing these steps gives me nice quality, lightweight (comparably – 280k) images that I can use for my blog. The final product:

Creating Quality Web Sized PNGs with Imagemagick

To simplify the process, I wrote a script to make it easier:

# resize-image-new - makes new image and resizes.

#ENHANCE - options to enhance image -enhance smoothes rough images

if [[ -z $NAME ]]; then
    echo "resize-image <WIDTHxHEIGHT> <original-image>"

# Convert (SIZE is proportional least value is used and only x needs specifid.)
convert -resize "$SIZE" -enhance "$NAME" "$RESIZEDNAME"

mogrify -colors $COLORS -depth $DEPTH "$RESIZEDNAME"

# Compress PNG
optipng -o5 "$RESIZEDNAME" 

I’d like to be able to learn if I could adapt this script to batch conversions.


Command Line to Clipboard

Update: Script has been updated to add pipe support. Thanks to Nathan who allowed me to use his improvements.

It’s really something to be learning Linux. The more I learn about Linux the more I learn it’s about manipulating letters and numbers (well, this is more programming than anything but Linux is a lot about that). Bash I’m discovering is great; I’m just getting into it and now have made things a good deal easier by learning how to copy and paste text from the command line via the Xorg server clipboard. Here is a couple commands that can do it with examples, following them are a couple bash scripts that make this easy as can beasy.

The Programs

xsel and xclip are command line programs that can redirect the contents of the Xorg server clipboard. The Xorg server has two clipboards: the common right-click > Copy, and one for the middle-mouse click. For those that don’t know of it yet, the middle-click clipboard allows quick copy and pasting without having to enter a menu or using Ctrl + v. Anytime you select text on the Xorg server there is a separate register that records this text, then clicking the middle-mouse button (sometimes called the mouse button three [usually done by clicking down the scroll wheel] will paste the text. The Xorg server defines the the middle-click clipboard as primary and the right-click clipboard as secondary.


Here are the basics of using xclip. xclip, I prefer over xsel because I have found that xsel can have problems pasting to java apps.

xclip can be used in a variety of ways. First, for example, it can be piped to:

echo "hi" | xclip -selection clipboard

This will copy to the standard clipboard. For abbreviation, you can use c instead of clipboard. You can specify primary or p here too to copy to the middle-mouse button, but isn’t necessary as this is the default for xclip.

echo "hello" | xclip

To direct a file to xclip the -in or -out options are needed:

xclip -in -selection c <filename>
xclip -out -selection c <filename>

Which will respectively put a file into the clipboard, and write to a file from the clipboard contents.

To make the process quicker, I’ve created a couple scripts to automate the tasks called cb-in and cb-out and can be used like a standard command:

cb-in pack 
 File pack copied to the clipboard




To copy to the context-menu clipboard:

xsel --clipboard < /etc/fstab

To copy a text to the middle mouse button clipboard:

xsel < /etc/fstab

xsel can be piped too:

echo "a-bit-of-text" | xsel -b
cat /etc/make.conf | xsel -b

To output directly to the terminal:

xsel --clipboard

And to redirect and append to a file:

xsel --clipboard > Baada-Boom.txt
xsel --clipboard >> ~/.Baada-Boom

cp2clip (xsel)

# cp2clip - copy to the clipboard the contents of a file

# Program name from it's filename

# Text color variables
bldblu='\e[1;34m'         # blue
bldred='\e[1;31m'         # red
bldwht='\e[1;37m'         # white
txtbld=$(tput bold)       # bold
txtund=$(tput sgr 0 1)    # underline
txtrst='\e[0m'            # text reset


# Display usage if full argument isn't given
if [[ -z $filename ]]; then
    echo " $prog <filename> - copy a file to the clipboard"

# Check that file exists
if [[ ! -f $filename ]]; then
  echo -e "$warn File ${txtund}$filename${txtrst} doesn't exist"

# Check user is not root (root doesn't have access to user Xorg server)
if [[ $(whoami) == root ]]; then
  echo -e "$warn Must be regular user to copy a file to the clipboard"

# Copy file to clipboard, give feedback
xsel --clipboard < "$filename"
echo -e "$pass ${txtund}"${filename##*/}"${txtrst} copied to clipboard"

clippaste (xsel)

# clippaste - Paste contents of clipboard to file in terminal.
# use 'xclip -out -selection primary' for middle click clipboard

# Program name from it's filename

# Text color variables
bldblu='\e[1;34m'         # blue
bldred='\e[1;31m'         # red
bldwht='\e[1;37m'         # white
txtbld=$(tput bold)       # bold
txtund=$(tput sgr 0 1)    # underline
txtrst='\e[0m'            # text reset

pasteinfo="clipboard contents"

# usage if argument isn't given
if [[ -z $filename ]]; then
  echo "clippaste <filename> - paste contents of context-menu clipboard to file"

# check if file exists, prompt to append or override, else create new
if [[ -f $filename ]]; then
  echo -en "$warn File ${txtund}$filename${txtrst} already exists - (${txtbld}e${txtrst})xit, (${txtbld}a${txtrst})ppend, (${txtbld}o${txtrst})verwrite: "
  read edit
  case "$edit" in
    [aA] )  xsel --clipboard >> $filename
            echo -e "$pass File ${txtund}$filename${txtrst} appended with clipboard contents"
    [oO] )  xsel --clipboard > $filename
            echo -e "$pass File ${txtund}$filename${txtrst} overwrote with clipboard contents"
    * )     exit
    esac; else
    xsel --clipboard >> $filename
    echo -e "$pass File ${txtund}"$filename"${txtrst} created with clipboard contents"

Purge memory trick

Purge Memory

Linux does a good job when it comes to memory allocation. If memory isn’t being used or hasn’t been used for awhile it gets put into a cache where it can readily pulled. At times though this cache can become pretty big (especially for a program that has a memory leak). If a good number of programs are being used or if memory is limited then Linux will begin using hard disk swap which can really bog down performance. In these instances, it may help to purge the memory.

In the terminal type free -m to see memory usage. Flushing the filesystem buffers and to drop extra caches can be done by doing:

sudo sync
sudo echo 3 | sudo tee /proc/sys/vm/drop_caches

Look once more at free -m and memory usage should be improved. Freeing memory is most effective by shutting down whatever programs can be. To be really effective shutdown X server first.

This can be put in a script if you need to regularly do this:


Background a Process/Program

At times it is useful to see the output of what a program produces by typing its command line name in the terminal (for instance for debugging), at other times typing a program in the terminal just takes up space that could ordinarily be utilized for something else. Launching programs from the terminal can be put in the background easily with a bash script.

nohup is used to prevent hangups and then you redirect the output of the command to /dev/null (the great Linux blackhole). Here’s the script:

Then in the terminal use the bgcmd command with whatever program needed to be put in the background:

Backgrounding Already Running Processes

Already running applications can be backgrounded as well. First type Ctrl + Z to release the application, then use bg to background it’s output.

Keep in mind though that if the terminal or tab is closed the program will close with it. Also too the bg command doesn’t suppress all output.

Cron Alarm Clock

Surprisingly I found out that there are a lack of alarm clocks in Linux. I’ve tried a few but really was impressed with none. So I decided to go with what the Linux uses for some of it’s timed events: Cron. Cron can be a good alarm and its easy to use.

The program crontab is used to create and edit cron jobs and the cron daemon checks for cronjobs a the top of every minute. A command line mp3 player can be used here but I like use Audacious. Crong will need to be told what X display to play Audacious on to discover the current display:

env | grep DISPLAY

Then as regular user edit crontab:

crontab -e

Here’s the cronjob layout representation:

#   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).
#   |   |   |   |   |   commands

Enter the time (multiple times, days need to be separated with commas) and the script to execute for the alarm. The asterik can be used (*) to satisfy all variables. Here’s mine for audacious:

07  21  *   *   1,2,3,4,5   env DISPLAY=:0.0 audacious /home/user/My\ Music/Other/Alarms/301gq.mp3

I found some good alarm tracks at this site the were perfect for the task.

To list the crontab do:

crontab -l 

Additional Information

Other Options


Wmtimer works well for Gnome users (KDE has kalarm) it leaves a small window on the screen which can’t be hidden but it is able use the system beep or execute a command on an alarm/timer event. Starting it from the command line is pretty easy:

wmtimer -a -t 18:39:00 -e "mpg321 ~/Music/Other/Alarms/301gq.wav"


Audacious also has alarm ability but it’s buried DeeeEEep in it’s preferences ( Preferences > Plugins > General ).

Alarm Clock

Thats actually its name. Despite the unexciting name, Alarm Clock is a very nice addition. Its a python script for the Gnome desktop that has the ability to run an application, display a message, and to use as a tray icon. Its a good application and easy to install.


Zenity Alert

Zenity is Gnome’s notification program. This won’t get a person out of bed but it can be good for reminders. In crontab enter:

Note: I wasn’t able to get this to work. If anyone can figure it out please let me know.

    23  15  *   *   * env DISPLAY=:0:0 notify-send -i gtk-info "libnotify          example" "An example of libnotify notification thingy."

Setting Up Irssi

Irssi is a command line client for IRC, developed since 1999 and written in the beautiful language of C. It is a very good client with a lot of options for those willing to learn a command line interface. If not, check out Xchat.

When I came upon a couple of install problems I was recommended to connect to the Gentoo freenode channel with and IRC client. I’ve used IRC before (really got into mIRC in Windows, had a brief foray of Xchat) and discovered that IRC is a pretty good way to meet people and exchange information. Xchat to me was just to difficult to set up as I liked (and I felt that I was missing something using it). When I used mIRC, BitchX was all the talk. Now irssi is and have been using it for years.

Installing Irssi

Install irssi however you distro tells you to.

I’m the type of person that learns by getting my hands dirty-and-tweaking-and-learn-by-example so I didn’t comb through all the pages of documentation but this guide should be enough to create a basic setup. If you’re like me the minimum that needs to be done is to comb through the starter’s guide and get feel of it. Irssi installs very very raw with really nothing set up so I added the few tweaks they recommend. After doing that I fire up irssi and set my Nick:

/set nick NICKNAME

Irssi saves the name between sessions but it won’t be reserved that will be done after a few more steps.

Freenode is a great project that hosts a lot of open source channels, including a lot of Linux distro help channels. If you ever run across them be sure to thank them, they do a great deed. To connect to a server:


And join a channel by doing (for example):

/j gentoo

Irssi is actually pretty easy. Another I like doing is automatically joining a network when irssi starts. Typing /network show the pre-configured networks. If your irssi is set up like mine, Freenode isn’t one of the default servers built in. If it’s not add it so it will make connecting quicker in the future:

/server add -auto -network Freenode 6667

The -auto command is optional if choosing to use it will automatically connect to that server when irssi starts. Nicks can be associated with a network:

/network add -nick Gen2ly Freenode

And channels in networks can be automatically set to be joined by doing:

/channel add -auto #gentoo Freenode

Setting up Freenode

The freenode faq is in good working order and can explain in better detail more about what freenode is and what a user can do. I just needed to register (this also reserves) my nickname:

/msg nickserv register <password> <email>

Responding to the email will be necessary of the registration will be dropped.

To keep the Nick’s email hidden:

/msg nickserv set hidemail on

Login to Freenode so your nick is official, though this too can be done automatically:

/msg nickserv identify <password>
/network add -autosendcmd "/msg nickserv identify <password> ;wait 2000" Freenode

Identd and irssi

Note: Some servers require an identification daemon (identd) to be installed (linux-identd, for example).

Basic Commands

It’s not really necessary to read any more documentation unless more advanced functions are needed. Most of the basic commands can be seen with:


The /help command should provide all the information necessary to use it. The only commands I use are /j, /leave, /msg user, /away, and /quit.

The basic key presses are: Alt+1, Alt+2,… to switch between windows; and PageUp to PageDown to scroll up and down.

Tips and Tricks

If you’re in channels with a lot of people, seeing all the joins, parts, quits, afks can be distracting, they can be turned off with:

/ignore #channelname ALL -PUBLIC -ACTIONS

Or you can ignore them in all channels by using * instead of #channelname.

With a rambler or someone wanting to ignore they can be ignored for a specific amount of time by doing:

/ignore -time 3600 <nick>

to ignore them for an hour.



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