Valid Echo command?

gnuoob · 06-10-2018, 03:46 PM

Hello,

I have a tinkering question with the BASH terminal and wondered if the following command is workable or I'm just doing something outside of the box of reality.

$: echo "New_Line#3" >> file*.txt

In said folder I have two text files named 'file1.txt' and 'file2.txt'

I can't get it to work but is it even possible?

Thank you in advance

scasey · 06-10-2018, 04:13 PM

That command will append the string

Quote:

New_Line#3

into a file named

Quote:

file*.txt

If run a second time, it will append another line to the same file.

You'd need to use tee to direct the output of echo to two different files, and you'd need to name them both.

Code:

echo "New_Line#3" | tee file1.txt >> file2.txt

See man tee

I'd be more inclined to do

Code:

echo "New_Line#3" >> file1.txt; cp file1.txt file2.txt

gnuoob · 06-10-2018, 04:38 PM

Thank you for the reply.

I was thinking I could use the wild card to put the same new test into a series of files but that is not the case.

In my scenario I wasn't looking to copy 1 to 2 but was instead just trying to add New_Line#3 to the end of a multiple of files.

gnuoob · 06-10-2018, 04:41 PM

my other attempts of using

$: echo "New_Line#3" >> file[1,2].txt

&

$: echo "New_Line#3" >> file?.txt

were just as unfruitful

keefaz · 06-10-2018, 05:02 PM

Use a loop

Code:

for f in file*.txt; do echo "New_Line#3" >> $f; done

ondoho · 06-11-2018, 12:09 AM

Quote:

Originally Posted by gnuoob

$: echo "New_Line#3" >> file[1,2].txt

&

$: echo "New_Line#3" >> file?.txt

were just as unfruitful

all these wildcards work, but the expansion doesn't do what you want it to do:

Code:

touch file{1,2} # works as expected because touch can take multiple filenames
echo file{1,2}
echo file*
echo file?

each time you get

Code:

file1 file2

as output.

so now try

Code:

echo "New_Line#3" >> file1 file2

it appends only to file1, because the >> operator doesn't know that there's another file after the first one.

X-LFS-2010 · 06-14-2018, 03:40 AM

Quote:

Originally Posted by keefaz

Use a loop

Code:

for f in file*.txt; do echo "New_Line#3" >> $f; done

that's what I do, what I've always seen the "old Unix hackers" do. that probably means it's the designed method for doing it.

you could write a C program to do what your thinking or even re-compile bash hacked to do that: but you couldn't get it documented in millions of Unix manpages or distributed to others. only you would be using it.

if you wrote a program to build software and included it: it wouldn't work on anyone else's system but your own - you could not share your scripts

pan64 · 06-14-2018, 04:01 AM

you cannot redirect anything into more than one file, redirection is unable to handle it.

but actually tee can do that for you:

Code:

echo "New_Line#3" | tee -a file*.txt >/dev/null

(not tested)

keefaz · 06-14-2018, 09:11 AM

Quote:

Originally Posted by pan64

you cannot redirect anything into more than one file, redirection is unable to handle it.

but actually tee can do that for you:

Code:

echo "New_Line#3" | tee -a file*.txt >/dev/null

(not tested)

Just tested, works nice