4 ms·

The "-n" option was added to UNIX around v6. The "-n" special case opened the floodgates for many more options. And what if I actually wanted to print "-n"?

The "-n" option was added to UNIX around v6. The "-n" special case opened the floodgates for many more options. And what if I actually wanted to print "-n"? There's no way to do it.

ilikejam 15y ago
Sure you can: dave@cronus $ ./echo -n "-n dave@cronus > " -n dave@cronus $ Not pretty, though.
- mikelward 15y ago
  You're right. I should have said "no sane way to do it". :-)
- martinp 15y ago
  Or echo -en "-n\n".
- mturmon 15y ago
  Cute, but does not work with bash builtin echo, for which two -n's equals one -n. bash-3.2$ echo -n -n foo foobash-3.2$ Like always with echo -n, no matter what you try, it's not portable.
  - ilikejam 15y ago
    So... [dave@mini ~]$ echo -n "-n foo > " -n foo [dave@mini ~]$ Easy!
    - mturmon 15y ago
      All respect for persistence, but that's not a solution, because the OP wanted to echo just "-n". I put the foo in to better show what was happening. For similar reasons, echo "" -n does not work, etc.
      - ilikejam 15y ago
        ' echo -n "-n " ' works fine with the bash built-in. It echo's "-n".
bch 15y ago
> And what if I actually wanted to print "-n"? There's no way to do it. Good point.I first tried "echo \-n", and "echo -- -n". No luck. I get the correct visual effect with "echo - ^Hn" (^H generated with ^V, backspace), but the embedded backspace is still actually part of the output :P "echo - ^Hn | col" strips it. Seems like quite an oversight, really, and is prime example of how bugs sneak into code via features. edit: ilikejam solved it w/o leaning on other tool. As he said "not pretty", but simpler than what I have: http://news.ycombinator.com/item?id=2781034 http://news.ycombinator.com/item?id=2781034
- pyre 15y ago
  Use the source... ;-) % env POSIXLY_CORRECT=1 echo -n -n Also note that if your shell is Bash, then your echo is a built-in: % type echo echo is a shell builtin That's why 'env' is necessary.
  - bch 15y ago
    Your Linux is showing ;). kamloops$ uname -s NetBSD kamloops$ echo $0 sh kamloops$ env POSIXLY_CORRECT=1 echo -n kamloops$
deleted 15y ago
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AlecSchueler 15y ago
`echo -e -\\x6E` works in GNU echo and Bash builtin (and likely others).
bdonlan 15y ago
The printf utility works far better if you want detailed control of your output: printf "%s\n" -n

The "-n" option was added to UNIX around v6. The "-n" special case opened the floodgates for many more options. And what if I actually wanted to print "-n"? There's no way to do it.

ilikejam 15y ago

Sure you can: dave@cronus $ ./echo -n "-n dave@cronus > " -n dave@cronus $ Not pretty, though.

mikelward 15y ago
You're right. I should have said "no sane way to do it". :-)
martinp 15y ago
Or echo -en "-n\n".
mturmon 15y ago
Cute, but does not work with bash builtin echo, for which two -n's equals one -n. bash-3.2$ echo -n -n foo foobash-3.2$ Like always with echo -n, no matter what you try, it's not portable.
- ilikejam 15y ago
  So... [dave@mini ~]$ echo -n "-n foo > " -n foo [dave@mini ~]$ Easy!
  - mturmon 15y ago
    All respect for persistence, but that's not a solution, because the OP wanted to echo just "-n". I put the foo in to better show what was happening. For similar reasons, echo "" -n does not work, etc.
    - ilikejam 15y ago
      ' echo -n "-n " ' works fine with the bash built-in. It echo's "-n".

bch 15y ago

> And what if I actually wanted to print "-n"? There's no way to do it. Good point.I first tried "echo \-n", and "echo -- -n". No luck. I get the correct visual effect with "echo - ^Hn" (^H generated with ^V, backspace), but the embedded backspace is still actually part of the output :P "echo - ^Hn | col" strips it. Seems like quite an oversight, really, and is prime example of how bugs sneak into code via features. edit: ilikejam solved it w/o leaning on other tool. As he said "not pretty", but simpler than what I have: http://news.ycombinator.com/item?id=2781034 http://news.ycombinator.com/item?id=2781034

pyre 15y ago
Use the source... ;-) % env POSIXLY_CORRECT=1 echo -n -n Also note that if your shell is Bash, then your echo is a built-in: % type echo echo is a shell builtin That's why 'env' is necessary.
- bch 15y ago
  Your Linux is showing ;). kamloops$ uname -s NetBSD kamloops$ echo $0 sh kamloops$ env POSIXLY_CORRECT=1 echo -n kamloops$

deleted 15y ago

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AlecSchueler 15y ago

`echo -e -\\x6E` works in GNU echo and Bash builtin (and likely others).

bdonlan 15y ago

The printf utility works far better if you want detailed control of your output: printf "%s\n" -n