[SOLVED] echo like printf

errigour · 08-06-2018, 11:12 PM

is there a way I can echo a value like printf would print it?
like if I did
printf("%3d", variable);
How can I do that with echo is it possible?

syg00 · 08-06-2018, 11:26 PM

Why would you want to ?. Bash (at least) has printf.

errigour · 08-06-2018, 11:43 PM

oh I didn't know that could you show me an example of using the variable $i printed with printf?
Im a novice at this stuff.

syg00 · 08-06-2018, 11:47 PM

The info on bash builtin commands can be a little hard to dig out - try "help printf" in this case.

Code:

z=3 ; printf "%04d\n" $z

errigour · 08-06-2018, 11:52 PM

got it heres what I did

Code:

printf "case %3d: return %s;\n" "$i" "$element"

errigour · 08-06-2018, 11:53 PM

thanx

orbea · 08-07-2018, 09:08 AM

I would suggest using proper quoting, note that "\n" is a literal new line while \\n, '\n' and "\\n" are not.

I personally use printf like this when simply printing output, it seems to work everywhere and is relatively fool proof.

Code:

$ foo=foo
$ bar=bar
$ printf %s\\n "$foo" "$bar"
foo
bar

mina86 · 08-07-2018, 03:49 PM

Quote:

Originally Posted by orbea

note that "\n" is a literal new line while \\n, '\n' and "\\n" are not.

That’s not true and you can verify it by running echo "\n". Inside of double quotes, backslash has special meaning only in front of dollar, back-tick, apostrophe, backslash or new-line character. See section 2.2.3 in Shell Command Language or Quoting section in bash man page. All of the sequences you’ve listed are equivalent.

NevemTeve · 08-08-2018, 03:00 AM

Off-topic note: even printf is platform-dependent: in some version, you only have \033 to print ESC character; in others \e and/or \x1b also works.

orbea · 08-08-2018, 11:00 AM

Quote:

Originally Posted by mina86

That’s not true and you can verify it by running echo "\n". Inside of double quotes, backslash has special meaning only in front of dollar, back-tick, apostrophe, backslash or new-line character. See section 2.2.3 in Shell Command Language or Quoting section in bash man page. All of the sequences you’ve listed are equivalent.

Thanks for the correction, I was mixing up things.

Edit: I see I was recalling this shellcheck warning, but it has since been retired due to being too pedantic.

https://github.com/koalaman/shellcheck/wiki/SC1117