Linux command to repeat a string n times

Question

Is there any built-in Linux command that allows to output a string that is n times an input string??

Answer 1

adrian@Fourier:~$ printf 'HelloWorld\n%.0s' {1..5}
HelloWorld
HelloWorld
HelloWorld
HelloWorld
HelloWorld
adrian@Fourier:~$

Answer 2

Here's an old-fashioned way that's pretty portable:

yes "HelloWorld" | head -n 10

This is a more conventional version of Adrian Petrescu's answer using brace expansion:

for i in {1..5}
do
    echo "HelloWorld"
done

That's equivalent to:

for i in 1 2 3 4 5

This is a little more concise and dynamic version of pike's answer:

printf -v spaces '%*s' 10 ''; printf '%s\n' ${spaces// /ten}

Answer 3

This can be parameterized and doesn't require a temp variable, FWIW:

printf "%${N}s" | sed 's/ /blah/g'

Or, if $N is the size of a bash array:

echo ${ARR[@]/*/blah}

Answer 4

Quite a few good ways already mentioned. Can't forget about good old seq though:

[john@awesome]$for i in `seq 5`; do echo "Hi";done
Hi
Hi
Hi
Hi
Hi

Answer 5

You can use a trick. Echoing an empty variable does not print anything. So you can write:

echo word$wojek{1..100}

If $wojek1 $wojek2 ... $wojek100 are non-existing variables you will get your word repeated 100 times without anything else.

Answer 6

Perhaps another way that is more general and useful for you:

adrian@Fourier:~$ n=5
adrian@Fourier:~$ for (( c=1; c<=n; c++)) ; do echo "HelloWorld" ; done
HelloWorld
HelloWorld
HelloWorld
HelloWorld
HelloWorld
adrian@Fourier:~$ 

The bash shell is more powerful than most people think :)

Answer 7

Repeat n times, just put n-1 commas between {}:

$ echo 'helloworld'{,,}
helloworld helloworld helloworld

Repeats 'helloworld' twice after the first echo.

Answer 8

POSIX AWK:

#!/usr/bin/awk -f
function str_repeat(s1, n1) {
   s2 = ""
   for (n2 = 1; n2 <= n1; n2++) {
      s2 = s2 s1
   }
   return s2
}
BEGIN {
   s3 = str_repeat("Sun", 5)
   print s3
}

Or PHP:

<?php
$s3 = str_repeat('Sun', 5);
echo $s3, "\n";

Answer 9

I've experienced broken pipe warnings with the yes solution, so here's another good alternative:

$ seq 4 | sed "c foo"
foo
foo
foo
foo

Answer 10

based on what @pike was hinting at

for every character in string echo string

echo ${target//?/$replace}

An example of a heading underlined with = characters

export heading='ABCDEF'; 
export replace='='; 
echo -e "${heading}\n${heading//?/$replace}"

will output

ABCDEF
======

This seems to port between linux and OS X and that makes me happy.

nJoy!

Answer 11

If you're on BSD, you can just use seq.

$ seq -f "Hello, world" 5
Hello, world
Hello, world
Hello, world
Hello, world
Hello, world

Answer 12

No magic here:

seq 5 | awk '{print "Hello World"}'

Answer 13

line="==========================="
line=${line:0:10}
${line//"="/"ten "}

outputs

ten ten ten ten ten ten ten ten ten ten

Answer 14

Assuming you want something like Perl's x operator, where you don't automatically get a newline between repetitions:

x() {
  # usage: x string num
  for i in $(seq 1 $2); do printf "%s" "$1"; done
  # print a newline only if the string does not end in a newline
  [[ "$1" == "${1%$'\n'}" ]] && echo ""
}

x Hi 10  # ==> HiHiHiHiHiHiHiHiHiHi

x $'Hello World!\n' 3

I explicitly used a for loop because you can't write {1..$n} in bash: brace expansion is done before variable substitution.

Answer 15

Not exactly built in to linux, but if you have python installed..

python
>>>var = "string"
>>>var*n

Or in one line, as commenter suggested:

python -c 'print "This is a test.\n" * 10'

Answer 16

Try this one:

echo $(for i in $(seq 1 100); do printf "-"; done)

Will create (a hundred dash):

---