Linux

Goal

To get Julia installed as a normal user on RHEL 6.

Motivation

“Julia talks like Python but walks like C.”

To do statistics more efficiently.

The compiled binaries often contain install scripts which put files to shared folders under /usr. Consequently, they have to be run as sudo privileges. That drove me to start this lengthy Julia compilation.

Installation

Without sudo privileges, I’ve chosen to compile Julia from source. I was too lazy to get the dependencies fixed. I just compiled it without GFortran and pkg-config under the ~/src folder.

Introduction

This article records my errors and difficulties encountered on the first day I came across Red Hat Enterprise Linux 7 in my school’s laboratory, as a normal user without sudo privileges.

The login screen was gdm, and the desktop environment was GNOME. IBus was used as the input engine.

Packages installed

The principal goal is to install tools that I usually use on RHEL without sudo permissions. To do so, I’ve downloaded the executable binaries or source code of these packages. As I wanted to focus on my studies, I prefer downloading executable binaries.

Background

While making changes to a theme for a static site generator, I changed files under a Git submodule included in the repo for my blog. (e.g. themes/beautifulhugo) That’s ideal for local testing, but not for version control. As a result, I cloned the repo for the theme to a directory separate from the one for my bloge (say, ~/beautifulhugo), and commit the changes there, then performed a Git submodule update so as to make the workflow clean.

Goal

To enable Chinese and Japanese input on (X)ubuntu 18.04 laptops .

My choices of input method

On my old Fujitsu laptop running Xubuntu, I’ve chosen Fcitx. This turns out to be a difficult choice when I install Rime.

Japanese input

Thanks to ひゃまだ, I’ve managed to switch between difference modes in Mozc.

Objective

To get a hands-on experience on Ubuntu installation on a UEFI hybrid system.

Devices

• 120 GB SSD disk: /dev/sda
• 1 TB HDD disk: /dev/sdb
• 8 GB USB key: /dev/sdc

Stage 0: precautions

• Ensure that your machine has enough power.
• Disable Secure Boot in M$ Windows
• Disable Quick Boot in boot menu

Stage 1: Make your live USB key

I tried Xubuntu’s built-in disk writing tool to create a live USB key from the official ISO file. Like my Xubuntu 18.04 installation on Fujitsu LH532 , the installer crashed during the installation. After submitting the generated report to Launchpad, I found out that the cause for this crash: the integrity test for my live USB key had failed.

It’s FOSS’s after-installation guide #11 recommends TLP. However, this package stopped my laptop from shutting down and logging in. I resorted to remove it through TTY.

pdfunite is fairly easy to use.

pdfunite PDF-sourcefile1..PDF-sourcefilen PDF-destfile

Another way is to use QPDF. I’ve learnt to add --empty from @qpdf/qpdf:#12.

qpdf --empty --pages *.pdf -- out.pdf

Problem

One can use xrandr to adjust screen brightness. However, the factor (default to 1.0) is relative to the current brightness. How to enable the brightness adjust keys / on the keyboard under Xubuntu 18.04?

Solution

Toz’s post on Ubuntu Forum works like a charm. The default value for GRUB_CMDLINE_LINUX is an empty string. Changing it to acpi_backlight=vendor and updating the GRUB has solved the problem since the next boot.

Rationale

My Linux Mint 18.3 installed on Clevo N240GU was a long-term support (LTS) version. Although the official page didn’t recommend an upgrade for its own sake, I still performed it as a result of my conversation with a technician in a computer store. He thought that the display problem in the current version would be fixed in this upgraded version.

The old version of Linux Mint couldn’t detect the onboard Intel graphics card. Therefore, sensors reported a higher CPU temperature and the display resolution couldn’t be correctly configured.

Easy Linux tips project recommends users to enable their firewall. However, this blocks all incoming traffic by default. If one wants to test the site on mobile devices, one will need to add a few rules to UFW.

$ sudo ufw allow ssh
$ sudo ufw allow http
$ sudo ufw allow https
$ sudo ufw allow 80/tcp
$ sudo ufw allow 1313/tcp comment "hugo server"

I learnt the last line from 竹内電設.