How do I echo to both standard out and to a file?

Br. Nicholas · 10-11-2004, 01:06 AM

Does anyone know of a way to echo to both standard out and to a file at the same time?

I'm writing a script, and I'd like to echo text to both standard out and append it to a log file, preferably at the same time. Is there any way I can do that in one command?

I've tried things like
echo "test echo" 2>> logfile
and a few things with piping |

But nothing seems to work.

I'd greatly appreciate any help anyone can give me.

With kind regards,

Peter, hieromonk

mirradric · 10-11-2004, 01:19 AM

Code:

man tee

Br. Nicholas · 10-11-2004, 08:50 AM

Thank you, but unfortunately, this doesn't seem to work with the echo command. "tee" works fine with things like the "date" command, but if you try to use it with the "echo" command, it just gets echoed along with everything else.

eg.

echo 'test echo' tee -a log.file

echoes "test echo tee -a log.file" to stdout, and writes nothing in the log file.

echo 'test echo' | tee -a log.file

echoes "test echo" to stdout, and writes nothing in the log file.

So how do I get this to work with echo? And yes, I've already looked at "man echo", and it didn't help. I *always* search before I ask...

Again, I hope someone can help me.

fp

mirradric · 10-11-2004, 08:56 AM

hmm... It works for me...

mirradric · 10-11-2004, 09:08 AM

If it's printing to stdout then it is piping and tee is getting the pipe*. Somehow it's not writing it to the file. Do you have write permission to the file? But it works for other commands.... I have no idea.

edit: *The other posibility is that the pipe is entirely broken.

mirradric · 10-11-2004, 09:13 AM

could you have by some chance permanently redirected echo's stdout to stderr.

say do you have

alias echo="echo >&2"

somewhere? I tried this and I got your result.

mirradric · 10-11-2004, 10:24 AM

Maybe you can test using

Code:

echo something | wc

if your output is

Code:

something
0 0 0

then your echo is print to stderr instead of stdout

Br. Nicholas · 10-12-2004, 12:45 AM

Please forgive me, but I got called away... unfortunately for the day. But with both bosses away now, that shouldn't happen again for a while.

mirradric -- exactly what worked for you?

Yes, I have permission for the file. I'm running as root.

How would I know if the pipe is broken? And how would I fix it?

How would I know if I have alias echo="echo >&2" somewhere? Where would I need to look?

echo something | wc gives me
1 1 10

What does that mean?

I really appreciate your help, by the way.

Br. Nicholas · 10-12-2004, 12:57 AM

BTW, I don't know if it is related, but I have another script that I run with a cron job which always gives me this error at the end:

stderr is not a tty - where are you?

Any ideas?

I'm running slack 9.1, if it matters.

mirradric · 10-12-2004, 01:05 AM

Quote:

Originally posted by Br. Nicholas
echo something | wc gives me
1 1 10

What does that mean?

It means that the output from echo is indeed piping to wc and the pipe works fine.

Quote:

mirradric -- exactly what worked for you?

I'm saying that

Code:

echo something | tee -a logfile

works for me.

Let me try to think of something...

mirradric · 10-12-2004, 01:42 AM

I'm at a lost, but let's try to diagnose and narrow down the problem. Something might pop up along the way.

First, you mentioned that

Code:

date | tee -a logfile

works, so the problem is not likely to be either tee or bash's pipes. Maybe you can try other programs and see if they work as well. Anyway so far the problem seems to be with echo.

Second,

Code:

#echo something | wc
1 1 10

seems to imply that echo is indeed printing to stdout.

Maybe you can try

Code:

alias echo

to see if any alias for echo have been defined.

Also check that you get the following results (which I think you'll get based on the wc test)

Code:

#echo something > filea 
#echo something 2> fileb
#cat filea
something
#cat fileb
#

Does echo something | tee -a logfile work as a normal user but not as root?
BTW, I'm not implying that you run the commands as root by using # as the shell prompt. Run them as whichever acct that gives you the problem.

got to go for tutorial. will check back with you if I think of anything else.

Br. Nicholas · 10-12-2004, 03:09 PM

I thought I tried this (echo something | tee -a logfile
), but apparently I must not have. I was very tired last night when I finally was able to look at this problem again, so maybe I didn't. But this seems to work fine.

Thank you very, very much. I was able to cut about 50 lines of code out of this script, and it makes it a lot easier to understand.

I appreciate all of your help very, very much.

With very kind regards,

Peter, hieromonk