Mastering Linux printf: Formatting and Data Output Techniques

printf: Format and Print Data

Function Description

printf command imitates the C language printf() function.

The purpose of printf is to output text according to a specified format. Unlike echo, printf does not automatically add a newline; you must add \n manually.

Command Syntax

printf  [options]  [text1]  [text2] ...

Option Meanings

\a

: alert character, usually the ASCII BEL character \n: newline \r: carriage return \0ddd: represents a character with 1‑3 digit octal value \ddd: represents a character with 1‑3 digit octal value, valid only in format strings

Reference Examples

(1) String output:

# printf "Hello, World
"
Hello, World

(2) Using format specifier "%s" for output:

# printf "%s
" a b c d
a
b
c
d

# printf "%s %s 
" a b c d
a b
c d

# printf "%s %s %s 
" a b c d e f
a b c
d e f

(3) Script demonstrating printf's power:

# vim printf.sh
printf "%-10s %-8s %-4s
" Name Gender Weightkg
printf "%-10s %-8s %-4.2f
" ZhangSan Male 59.5278
printf "%-10s %-8s %-4.2f
" LiSi Male 62.7323
printf "%-10s %-8s %-4.2f
" WangWu Female 49.8767

Execution result:

# sh printf.sh
Name      Gender   Weightkg
ZhangSan  Male     59.53
LiSi      Male     62.73
WangWu    Female   49.88

%s %c %d %f are format specifiers. %-10s specifies a field width of 10 characters; “-” left‑aligns, otherwise right‑aligns, padding with spaces if needed. %-4.2f formats a floating‑point number with two decimal places.

(4) Adding parentheses around a,b,c,d:

# printf "( %s )" a b c d; echo ""
( a )( b )( c )( d )