Display format/color text on the shell

-
Terminals can display texts in color as well as allow formatting with the help of escape sequences.

Escape Sequence = Escape Character + FormatCode+'m' = "<esc>[FormatCodem"

Escape character can be '\e', \033, \x1B

The format code for Red is 31, so to print the Text in Red.

echo -e '\033[31mHello World'

The -e option of the echo command enable the parsing of the escape sequences.

If you want the background to be Red the format code is 41.

echo -e '\033[41mHello World'

We can add multiple format codes with a ; as delimeter

 echo -e '\033[42;31mHello World'

To remove all formatting, the format code is 0.

echo -e '\033[31mHello \033[0mWorld'

It is better to add \033[0m at the end of each colored text.

To Bold the text, the format code is 1.

echo -e '\033[1mHello World'




You can find more format codes in the below link:


Comments

Post a Comment

Popular posts from this blog

bb.utils.contains yocto

-
Image
bb.utils.contains  is most commonly used function in Yocto. grep in poky directory returned with 696 count. $ grep -nr 'bb.utils.contains' poky/ | wc -l 696 It's definition is present in 'poky/bitbake/lib/bb/utils.py' file This function returns third argument if the second argument is subset of the first argument else returns fourth argument Let's take an example to understand this. You can see from the above screenshot, when the second argument is a subset of first argument, "present" was returned, else "notpresent" was returned We can also use bb.utils.contains inside if loop. This we can use inside a recipe. if ${@bb.utils.contains('SOMEFLAG','NEWVALUE3','true','false',d)}; then     FOO = 'HELLO' fi
Read more

make config vs oldconfig vs defconfig vs menuconfig vs savedefconfig

-
Image
Building the Linux Kernel is a two-step process: Configuring the Kernel options Building the Kernel with those options. There are many methods available for configuring the kernel. make config: Text-based Configuration.  Options are prompted one after another. All options need to be answered Access to former options is not possible make menuconfig: Menu-driven user interface Allows to navigate forwards and backward directly between features Allows to load and save files with filenames different from ".config" Provides search feature It uses ncurses library for GUI. If the ncurses library is not installed, make menuconfig option fails. To install ncurses library on Ubuntu: sudo apt-get install libncurses5-dev make defconfig: Creates a ".config" file with default options from the ARCH supplied defconfig Configurations are generally stored in the directory: arch/$(ARCH)/configs $ ls arch/x86/configs/ i386_defconfi
Read more

PR, PN and PV Variable in Yocto

-
PN : Represents the name of the recipe. The name is usually extracted from the recipe file name. PR:  Represents the revision of the recipe. Default value for this revision is "r0". Subsequent revisions of the recipe conventionally will have "r1", "r2" and so on. PV:  Represents the version of the recipe. Normally extracted from the recipe file name. For example: ffmpeg_3.4.2.bb recipe. ${PN} : ffmpeg ${PV} : 3.4.2
Read more