Add prefix to each word of each line in bash

Question

I have a variable called deps:

deps='word1 word2'

I want to add a prefix to each word of the variable.

I tried with:

echo $deps | while read word do \ echo "prefix-$word" \ done

but i get:

bash: syntax error near unexpected token `done'

any help? thanks

Answer 1

For well behaved strings, the best answer is:

printf "prefix-%s\n" $deps

as suggested by 123 in the comments to fedorqui's answer.

Explanation:

• Without quoting, bash will split the contents of $deps according to $IFS (which defaults to " \n\t") before calling printf
• printf evaluates the pattern for each of the provided arguments and writes the output to stdout.
• printf is a shell built-in (at least for bash) and does not fork another process, so this is faster than sed-based solutions.