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bashconsoleformattingecho
JamesRat
JamesRat

Reputation: 3810

How does one output bold text in Bash?

I'm writing a Bash script that prints some text to the screen:

echo "Some Text"

Can I format the text? I would like to make it bold.

Upvotes: 365

Views: 305976

Answers (4)

psmears
psmears

Reputation: 28000

The most compatible way of doing this is using tput to discover the right sequences to send to the terminal:

bold=$(tput bold)
normal=$(tput sgr0)

then you can use the variables $bold and $normal to format things:

echo "this is ${bold}bold${normal} but this isn't"

gives

this is bold but this isn't

Note that normal will turn off all formatting (so if you have other formatting - such as colours - that will be disabled, too).

Upvotes: 608

Aviv
Aviv

Reputation: 14467

In order to apply a style on your string, you can use a command like:

echo -e '\033[1mYOUR_STRING\033[0m'

Explanation:

  • echo -e - The -e option means that escaped (backslashed) strings will be interpreted
  • \033 - escaped sequence represents beginning/ending of the style
  • lowercase m - indicates the end of the sequence
  • 1 - Bold attribute (see below for more)
  • [0m - resets all attributes, colors, formatting, etc.

The possible integers are:

  • 0 - Normal Style
  • 1 - Bold
  • 2 - Dim
  • 3 - Italic
  • 4 - Underlined
  • 5 - Blinking
  • 7 - Reverse
  • 8 - Invisible

All this is per ANSI but is implemented by absolute majority of terminal emulators out there. An alternative way to style output is to rely on terminfo through use of the tput command. The latter will most likely output escape sequences which are ANSI anyway, unless you're at a really obscure and/or exotic type of terminal.

Upvotes: 216

roufamatic
roufamatic

Reputation: 18485

In theory like so:

# BOLD
$ echo -e "\033[1mThis is a BOLD line\033[0m"
This is a BOLD line

# Using tput
tput bold 
echo "This" #BOLD
tput sgr0 #Reset text attributes to normal without clear.
echo "This" #NORMAL

# UNDERLINE
$ echo -e "\033[4mThis is a underlined line.\033[0m"
This is a underlined line.

But in practice it may be interpreted as "high intensity" color instead.

(source: http://unstableme.blogspot.com/2008/01/ansi-escape-sequences-for-writing-text.html)

Upvotes: 25

Michał Trybus
Michał Trybus

Reputation: 11784

I assume bash is running on a vt100-compatible terminal in which the user did not explicitly turn off the support for formatting.

First, turn on support for special characters in echo, using -e option. Later, use ansi escape sequence ESC[1m, like:

echo -e "\033[1mSome Text"

More on ansi escape sequences for example here: ascii-table.com/ansi-escape-sequences-vt-100.php

Upvotes: 53

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