Why can't echo and printf output variables that have only whitespace characters?

Question

var1=$(printf "\n\x0A\n")

var2=$(printf "\na\nb\nc")

Using Android Terminal, the output of echo -e "$var1" (same for echo and printf) iss nothing, not even the 3 new lines. But echo -e "$var2" or echo "$var2" or printf "$var2" output:

a
b
c

How come $var2's output includes the whitespace character but not $var1?

(\n and \x0A have the exact same behaviour.)

Possible duplicate of Why does shell Command Substitution gobble up a trailing newline char? (note that it's not just one trailing newline - all trailing newline characters are removed) — muru, May 10 '19 at 09:25
Also see: https://unix.stackexchange.com/questions/383217/shell-keep-trailing-newlines-n-in-command-substitution — muru, May 10 '19 at 09:26
Replace teh double quots with single quotes, and put everything after the = sign between double quotes — wurtel, May 10 '19 at 10:53
Note also that echo inserts a newline after the output, but printf does not. — Seamus, May 10 '19 at 13:20

score 0 · Answer 1 · answered May 10 '19 at 09:24

0

Why would you print a result of a printf?

var1="\n\x0A\n"
var2="\na\nb\nc"

printf $var1
printf $var2

that should work.

*nix system - LF, 0x0A (dec 10) \n as line ending

windows OS - CR LF, 0x0D 0x0A (dec: 13 10) \r \n as line ending.

answered May 10 '19 at 09:24

Michael D.

2,830

Why can't echo and printf output variables that have only whitespace characters?

1 Answers1