bash redirect output of command to file appended with space separator

Question

I'm running a large loop that calls a program that outputs a single value. I would like to redirect that output to a text file appended by a space rather than a new line. Is there any way to do this?

for i in {1..1000000000}; do
    mincstats file${i}.mnc -mean -quiet >> output.txt
done

I have tried assigning the output to a variable as below, but I think this may be taking up unnecessary processing time. What would be the most efficient way to do this?

for i in {1..1000000000}; do
    var=$(mincstats file${i}.mnc -mean -quiet)
    echo -n $var >> output.txt
done

echo is a built-in; it's not going to use any significant amount of time over what mincstats already requires. — chepner
– chepner, Commented Nov 6, 2015 at 20:51

Barmar · Accepted Answer · 2015-11-06 20:42:44Z

2

You could translate all the newlines to space.

It's also more efficient to do the redirection on the whole loop, instead of each command.

for i in {1..1000000000}; do
    mincstats file${i}.mnc -mean -quiet
done | tr '\n' ' ' >> output.txt

answered Nov 6, 2015 at 20:42

Barmar

789k57 gold badges555 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

123 Over a year ago

yep think this is the best way.

Jon Over a year ago

Thanks! both suggestions work, but this seems to run a little bit faster.

Cyrus · Accepted Answer · 2015-11-06 20:47:04Z

1

Try this:

for ((i=1;i<=1000000000;i++)); do 
  echo -n "$(mincstats file${i}.mnc -mean -quiet) "
done > output.txt

edited Nov 6, 2015 at 20:47

answered Nov 6, 2015 at 20:09

Cyrus

90.2k15 gold badges112 silver badges173 bronze badges

1 Comment

Barmar Over a year ago

You'll echo a newline after the space.

Collectives™ on Stack Overflow

bash redirect output of command to file appended with space separator

2 Answers 2

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related