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).

Command line to xclipboard

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"

Background a process or 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 hogs the prompt that could ordinarily be utilized for something else. Launching programs from the terminal can be put in the background easily and I’ve created a bash script to help out.

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

# Open a command in the terminal in the background.
# Add 'complete -cf bgcmd' to ~/.bashrc for command completion

nohup "$@" &> /dev/null &

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

bgcmd gedit ~/Documents/recipes.markdown

Backgrounding an already running process

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 that if the terminal or tab is closed the program will close with it; also too the bg command doesn’t suppress all output.