echo newline suppression [duplicate]

2019-04-26 18:31发布

This question already has an answer here:

Why doesn't $echo '-n' write -n on terminal although -n is written within single quotes ?

6条回答
别忘想泡老子
2楼-- · 2019-04-26 19:07

I found that the following just works in bash:

echo -n PRINT_THIS

So, you should put -n the first place.

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戒情不戒烟
3楼-- · 2019-04-26 19:18

Not quiete there:

echo -e 'a-n\b\b\b '
 -n

surprisingly this works:

echo -e '-n\b'
-n

and here a solution I can explain:

echo "foobar" | sed 's/.*/-n/'
-n
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ら.Afraid
4楼-- · 2019-04-26 19:21

The quotes don't help because ... ugh, it's hard to explain. The shell strips the quotes off before the "echo" command itself is evaluated, so by that time they don't matter.

Try this:

echo - -n

That's not documented as working (I'm running Ubuntu Linux), but echo is almost certainly a built-in to whatever shell you're using, so the man page is questionable anyway. It does work for me. (I'm running zsh because I'm really suave and sophisticated).

edit: well it seems that the bash builtin edit doesn't behave that way. I don't know what to suggest; this:

echo '' -n

will give you "-n" preceded by a space, which (depending on what you're doing) might be OK.

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祖国的老花朵
5楼-- · 2019-04-26 19:24

Because the quotes are processed by the shell and the echo command receives plain -n. If you want to echo -n, you can e.g. printf '%s\n' -n

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看我几分像从前
6楼-- · 2019-04-26 19:25

You could try

echo -e '\055n'
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Luminary・发光体
7楼-- · 2019-04-26 19:28

you should try to use the more portable printf as far as possible.

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