Linux

22 Feb 2022 - linux

convert -density 150x150 -quality 20 -compress jpeg one.pdf two.pdf

How can I change the resolution of a JPG?

02 Jun 2019 - linux

Open the JPG file using GIMP. Then, open the Image menu and select Scale Image... Next, set the X and Y resolution to the desired resolution and save the file.

How can I convert and combine JPG to PDF?

01 Jun 2019 - linux

convert *.jpg output.pdf

If convert returns a not authorized error, edit /etc/ImageMagick-6/policy.xml and change the PDF rights from none to read|write.

References

https://askubuntu.com/a/1081724

How can I remove MP3 tags?

06 Jun 2018 - linux

id3v2 -D filename.mp3

References

https://unix.stackexchange.com/a/39194

How can I install glog?

31 Jul 2016 - linux

git clone https://github.com/google/glog.git
cd glog
./configure && make
sudo make install
Compile with flag -lglog

References

https://github.com/google/glog

How can I fix docker permission denied?

01 Aug 2015 - linux

Docker may give you the permission deniend error on Linux:

$ docker run busybox date
2015/08/01 15:37:42 Post
http:///var/run/docker.sock/v1.12/containers/create: dial unix
/var/run/docker.sock: permission denied

Run the following command and log out to fix the above error.

sudo usermod -a -G docker ${USER}

References

https://cloud.google.com/container-registry/#install_docker

How can I use vi key mappings in bash?

18 Nov 2014 - linux

Include following in ~/.bashrc:

set -o vi

References

http://apple.stackexchange.com/a/88528

How can I install the Opera browser on Ubuntu?

05 May 2014 - linux

sudo bash -c 'echo "deb http://deb.opera.com/opera/ stable non-free" > /etc/apt/sources.list.d/opera.list'
sudo apt-get install debian-archive-keyring
wget -O - http://deb.opera.com/archive.key | sudo apt-key add -
sudo apt-get update
sudo apt-get install opera

References

How can I install a recent version of gcc?

04 May 2014 - linux

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 50

Similar instructions work for installing other versions of gcc and g++.

References

http://askubuntu.com/a/271561

How can I replace a page of a PDF?

23 Mar 2014 - linux

pdftk A=f1.pdf B=f2.pdf cat A1-14 B A16-21 output f3.pdf

References

http://www.pdflabs.com/docs/pdftk-man-page/

How can I resize and convert an image?

22 Mar 2014 - linux

convert -resize 50% image.jpg image.pdf

References

http://www.imagemagick.org/script/convert.php

How can I install the missing dependency of Acrobat Reader?

28 Feb 2014 - linux

Install Adobe Reader 9 using its .deb file.

If you run Adobe Reader, you may get the following error message:

/opt/Adobe/Reader9/Reader/intellinux/bin/acroread: error while loading shared
libraries: libxml2.so.2: cannot open shared object file: No such file or
directory

If you get the above error message, run the following command:

sudo apt-get install libxml2:i386 libstdc++6:i386

References

http://askubuntu.com/a/410648

How can I install R?

01 Jan 2014 - R, linux

sudo apt-get install r-base

References

http://cran.r-project.org/bin/linux/ubuntu/README

How can I trace bitmap images to vector ones?

21 Dec 2013 - linux

Use xsane to scan your document as a PNM image.
Use potrace to covert your image to a vector image, e.g., PDF or EPS.

References

How can I install Ruby in Linux?

27 Nov 2013 - linux

Run the following command to install RVM.

\curl -sSL https://get.rvm.io | bash -s stable --ruby

The above command should report a message of the form below at the end:

To start using RVM you need to run source $HOME/.rvm/scripts/rvm in all your open shell windows, in rare cases you need to reopen all shell windows.

References

https://rvm.io/

How can I specify the folder containing the generated Jekyll site?

17 Jul 2013 - linux

New command:

jekyll serve -d _new_site

Deprecated command:

jekyll _new_site --server

References

http://jekyllrb.com/docs/configuration/

How can I tell if a JVM is 32 or 64 bits?

16 May 2013 - linux

If the running JVM is not 64 bits, the following command will report an error message:

java -d64 -version

References

http://stackoverflow.com/a/2062263

How can I tell if a binary is 32 or 64 bits?

15 May 2013 - linux

file /path/to/binary

References

http://stackoverflow.com/a/5103511

How can I install Orcale JDK 7?

06 May 2013 - linux

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer
sudo update-java-alternatives

References

http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html

How can I make a user a sudoer?

26 Apr 2013 - linux

sudo usermod -a -G sudo username

References

http://askubuntu.com/a/168289

How can I extract a page from a PDF?

21 Apr 2013 - linux

pdftk A=in.pdf cat A1 output out.pdf

References

http://www.linuxjournal.com/content/tech-tip-extract-pages-pdf

How can I install Citrix?

03 Apr 2013 - linux

Install OpenMotif.
Install Citrix.
- Download linuxx86-11.100.158406.
- Extract the downloaded archive.
- Run sudo ./setupwfc.
Run Citrix.
- /usr/lib/ICAClient/wfcmgr

References

How can I find the distribution of the running Linux?

21 Mar 2013 - linux

cat /etc/*-release

How can I install ant without GCJ?

20 Mar 2013 - linux

sudo apt-get install --no-install-recommends ant

When trying to use ant to build the X10 compiler, ant complained about a missing JAR. It looked like the build.xml file used javah targets. So, I installed ant-optional using the following command.

sudo apt-get install --no-install-recommends ant-optional

How can I revert the display settings?

19 Mar 2013 - linux

While tweaking the display resolution, it got messed up. So, I went and reverted /etc/X11/xorg.conf to a previous version. There was a command mentioned in this config file on how to force X11 update itself according to the new configurations.

How can I redirect stderr and stdout to a file?

18 Mar 2013 - linux

process >file 2>&1

How can I follow what gets appended to a file online?

17 Mar 2013 - linux

tail -f file

How can I install an SSH server?

16 Mar 2013 - linux

sudo apt-get install openssh-server

When an old client tries to connect to the server, it complains that the server has changed its identity. Remove the ~/.ssh/known_hosts to have the client receive the new identity of the server.

References

https://help.ubuntu.com/6.06/ubuntu/serverguide/C/openssh-server.html

How can I configure my SSH client to connect to a server?

15 Mar 2013 - linux

ssh-keygen -C "key-identifier" (without quotes)  
scp ~/.ssh/id_rsa.pub server.example.org
cat ~/id_rsa.pub >> ~/.ssh/authorized_keys

Create or open the file at ~/.ssh/config Add the following lines:

Host server.example.org
User git
Hostname server.example.org
PreferredAuthentications publickey
IdentityFile [local path to private key half of the public key you provided]

The main ssh config file is at /etc/ssh/ssh_config.

How can I copy the SSH public key to a remote host?

14 Mar 2013 - linux

ssh-copy-id remote-host

How can I scroll in the screen program?

13 Mar 2013 - linux

Press C-a [ to enter the copy mode. Then, press ESC to exit the copy mode.

How can I rename a screen window?

12 Mar 2013 - linux

Press CTRL-a A in each active window to get prompted for entering a new name.

References

http://nathan.chantrell.net/old-stuff/linux/an-introduction-to-screen/

How can I reorder screen windows?

11 Mar 2013 - linux

Switch to the window you’d like to move and press CTRL-a followed by :number x, where x is the new location of the window.

References

http://www.snowfrog.net/2007/11/07/howto-move-windows-in-gnu-screen/

How can I recover Grub after installing Windows?

10 Mar 2013 - linux

grub

sudo grub

Tell Grub which partition to tell the MBR your Grub is on by entering:

root (hd0,3)

If Ubuntu was installed on the second partition of the first hard-drive. Tell GRUB which drive’s MBR to fix:

setup (hd0)
quit

grub2

References

https://wiki.ubuntu.com/Grub2#Recover%20Grub%202%20via%20LiveCD

How can I set environment variables during startup?

09 Mar 2013 - linux

If you want to make an environment variable visible system-wide, you should set it in /etc/environment. To set environment variables per user, you have to modify ~/.pam_environment.

The following is a sample ~/.pam_environment file contents.

JAVA_HOME  OVERRIDE=/path/to/java/home
PATH       OVERRIDE=${PATH}:${JAVA_HOME}/bin

I’ve always had problems with ~/.pam_environment for it duplicates my entries in PATH. So, I use the system-wide configuration file, i.e., /etc/environment.

References

https://help.ubuntu.com/community/EnvironmentVariables
man pam_env
/etc/security/pam_env.conf

How can I install Dropbox?

08 Mar 2013 - linux

First, run the following command to add the Dropbox repository.

sudo add-apt-repository "deb http://linux.dropbox.com/ubuntu $(lsb_release -sc) main"

Next, run the command sudo apt-get update. You should get an error message similar to the following:

W: GPG error: http://linux.dropbox.com precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY FC918B335044912E

Follow the instructions at http://reprogrammer.github.io/faq/2013/02/24/how-can-i-install-ubuntu-repository-public-keys/ to add the necessary keys. While following the instruction, note that the Dropbox’s key server is pgp.mit.edu.

Finally, run the following commands to install Dropbox.

sudo apt-get update
sudo apt-get install dropbox python-gpgme

The command sudo apt-get update reports the following problem:

W: Duplicate sources.list entry http://linux.dropbox.com/ubuntu/ precise/main amd64 Packages (/var/lib/apt/lists/linux.dropbox.com_ubuntu_dists_precise_main_binary-amd64_Packages) W: Duplicate sources.list entry http://linux.dropbox.com/ubuntu/ precise/main i386 Packages (/var/lib/apt/lists/linux.dropbox.com_ubuntu_dists_precise_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems

I need to figure out how to resolve the duplicate entry problem.

References

http://askubuntu.com/a/127187

How can I install Alpine?

07 Mar 2013 - linux

sudo apt-get install alpine

Alpine stores its mails in $HOME/mail.

How can I install and uninstall TeXLive in Ubuntu?

06 Mar 2013 - linux, tex

Installation

sudo apt-get install perl-tk
wget http://mirror.ctan.org/systems/texlive/tlnet/install-tl-unx.tar.gz
tar xvfz install-tl-unx.tar.gz
sudo ./install-tl<tab>/install-tl -gui

Select the following two options:

Use the letter size instead of the default A4 size.
Create symlinks in system directories.

The installer asks about the following directories. Leave the default settings.

TEXDIR=/usr/local/texlive/<year>
TEXMFLOCAL=/usr/local/texlive/texmf-local
TEXMFSYSVAR=/usr/local/texlive/<year>/texmf-var
TEXMFSYSCONFIG=/usr/local/texlive/<year>/texmf-config
TEXMFHOME=~/texmf

The installer says the following, but the symlinks are enough.

Add /usr/local/texlive/20xy/texmf/doc/man to MANPATH.

Add /usr/local/texlive/20xy/texmf/doc/info to INFOPATH.

Most importantly, add /usr/local/texlive/20xy/bin/x86_64-linux.

Uninstallation

sudo tlmgr uninstall
rm -rf /usr/local/texlive

References

How can I update my TeXLive installation?

05 Mar 2013 - linux, tex

Updating the updater itself

sudo tlmgr update --self

Updating the updater itself and all the packages

sudo tlmgr update --self --all

Updating the TeXLive distribution

sudo tlmgr -gui

You can check if a package is installed by using the locate command. Sometimes, a package is installed but the symlink to it in system directories is missing. You can update the symlinks through the tlmgr program.

How can I install vanilla TeXLive to satisfy APT dependencies?

04 Mar 2013 - linux, tex

I used texlive.ctl to create a vanilla TexLive package. I removed tex-common from texlive.ctl because the original texlive.ctl file didn’t have it and I had to remove it to install hevea. The hevea package is not included in TeXLive. And, I had to install tex-common in order to install hevea. Also, to let my own installation of TeXLive locate the style files of the hevea package installed through Ubuntu, I had to set the following environment variable.

export TEXMFHOME=/usr/share/texmf/

I used the following command to set the “Standards-Version” field in texlive.ctl.

apt-cache show debian-policy | grep Version

Then, I executed the following commands to create and install my vanilla package.

equivs-build texlive.ctl sudo dpkg -i texlive-vanilla_2010-1~1_all.deb

Finally, I used the following command to install kile.

sudo apt-get --no-install-recommends install kile

See http://manpages.ubuntu.com/manpages/maverick/man5/deb-control.5.html to learn more about the format of Ubuntu package control files. Specifically, the “Provides” section lists virtual packages that could be provided by the normal package.

References

How can I install hevea on top of vanilla TeXLive?

03 Mar 2013 - linux, tex

I installed texlive-vanilla (2010-1~1). And, tried to install hevea with the following command.

sudo apt-get --no-install-recommends install hevea

But, I got the following message.

The following NEW packages will be installed:

  hevea ocaml-base-nox tex-common

So, I checked the dependencies of the hevea in Ubuntu. The hevea package requires “tex-common (>=2.00)”. The “provides” section of the control file of vanilla-texlive doesn’t specify the versions of the virtual packages. So, I thought all of the virtual packages get the version number 2010-1~1 automatically. Then, I used the following command to verify that “2010-1~1” is indeed greater than “2.00” according to Ubuntu package formate rules.

dpkg --compare-versions 2010-1~1 gt 2.00 ; echo $?

And, I got the value “0” on the console, which confirms that 2010-1~1 is greater than 2.00. At this point, I concluded that the version number of the virtual packages is unspecified. So, I decided to create my own version of tex-common. I created a control file for my tex-common package called tex-common.ctl and executed the following commands.

equivs-build tex-common.ctl sudo dpkg -i tex-common_2010-1~1_all.deb

Having installed my own tex-common package, I was able to successfully install hevea using the following command.

sudo apt-get --no-install-recommends install hevea

How can I set the number of floating point digits in bc?

02 Mar 2013 - linux

The following command sets the precision of floating point operations to 2 digits.

scale = 2

How can I type right to left?

01 Mar 2013 - linux

To write right-to-left in Linux, press Right-ALT+] and end by ALT+P.

To write left-to-right in Linux, press Right-ALT+[.

Use RLE and PDF to begin and end a right-to-left embedding. The unicode for LRE is U+202A, the unicode for RLE is U+202B and the unicode for PDF is U+202C. In Ubuntu, hold CTRL-SHIFT to type a unicode character. For example, to type an RLE, press the following keys: CTRL SHIFT U + 2 0 2 B.

Hold the left ALT and the right SHIFT keys to switch the Ubuntu keyboard layout.

References

http://www.unicode.org/reports/tr9/

How can I recover deleted files?

28 Feb 2013 - linux

The best tool that I found for recovering files was Photorec.

References

https://help.ubuntu.com/community/DataRecovery#Photorec

How can I generate a LaTeX diff of two LaTeX files?

27 Feb 2013 - linux, tex

Make sure old.tex and new.tex have a place to insert the preamble.

latexdiff --type=UNDERLINE --subtype=SAFE --floattype=FLOATSAFE old.tex new.tex > difference.tex

How can I pass the results of a command to another?

26 Feb 2013 - linux

The xargs program passes the outputs of one command as arguments to another one.

The following is an example of processing the results of find using xargs:

find . -name <pattern> -print0 | xargs -0 -I {} <command with {} as an argument>

find -print0 and xargs -0 make find and xargs handle files with unusual characters in their names properly.

References

How can I install the latest stable release of Git?

25 Feb 2013 - linux, git

The following commands install the latest stable release of git.

sudo add-apt-repository ppa:git-core/ppa
sudo aptitude update
sudo aptitude upgrade

References

How can I install Ubuntu repository public keys?

24 Feb 2013 - linux

If you get an error like the following from apt:

W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A6DCF7707EBC211F

Take the last 8 characters of the string in the error message and use it in the following two commands:

gpg --keyserver keyserver --recv 7EBC211F

The keyserver in the above commands may be a server like keyserver.ubuntu.com or pgp.mit.edu.

The above command will generate an output similar to the following:

gpg: requesting key 7EBC211F from hkp server keyserver.ubuntu.com gpg: key 7EBC211F: public key “Launchpad PPA for Ubuntu Mozilla Security Team” imported gpg: no ultimately trusted keys found gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1)

Next, run the following command:

gpg --export --armor 7EBC211F | sudo apt-key add -

The above command should generate the following output:

OK

Note the post at http://askubuntu.com/a/127187 suggest that the above two steps can be performed in a single steps. I need to try out this command.

sudo apt-key adv --keyserver keyserver --recv-keys 7EBC211F

References

http://www.univet.hu/users/jkis/Education/Linux/Linux_repositories.txt

How can I open a terminal from within nautilus?

23 Feb 2013 - linux

To open a terminal from within nautilus, install the nautilus-open-terminal package using the following command:

sudo aptitude install nautilus-open-terminal

References

http://ubuntu-tutorials.com/2007/05/13/nautilus-open-terminal-terminal-quick-launch/

How can I update the database used by the locate command?

22 Feb 2013 - linux

sudo updatedb

How can I fix the background color of Eclipse tooltips?

21 Feb 2013 - linux, eclipse

Open the file at /usr/share/themes/Ambiance/gtk-2.0/gtkrc. Locate tooltip_fg_color and tooltip_bg_color in the file and change their values as follows:

tooltip_fg_color:#000000
tooltip_bg_color:#f5f5c5

References

How can I clear the bash history?

20 Feb 2013 - linux

history -c && rm -f ~/.bash_history

References

http://www.infohit.net/blog/post/clear-bash-history.html

How can I get the specifications of the installed RAM?

19 Feb 2013 - linux

dmidecode --type memory

References

http://www.cyberciti.biz/faq/ubuntu-check-ram-memory-speed-specification-within-linux-machine/

How can I monitor the health of a hard disk?

18 Feb 2013 - linux

Use S.M.A.R.T.

References

https://help.ubuntu.com/community/Smartmontools

How can I install the latest release of Mercurial?

17 Feb 2013 - linux, mercurial

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-key 323293EE
sudo add-apt-repository ppa:mercurial-ppa/releases
sudo apt-get update
sudo apt-get upgrade

References

https://launchpad.net/~mercurial-ppa/+archive/releases

How can I open a shell within Vim?

16 Feb 2013 - linux

Get the latest tar.gz of conque from http://code.google.com/p/conque/downloads/list.

Extract the tar.gz file to get the directory conque_x.y. Execute the command cp -r conque_x.y/* ~/.vim/ to install Conque on your vim.

Table of Contents

grub

grub2

Installation

Uninstallation

Updating the updater itself

Updating the updater itself and all the packages

Updating the TeXLive distribution