Shell script: I have string "abc____def____ghi", how to make "abc def ghi"
 

It's silly, but I could not find examples for this.
I need to replace N number of _ with N number of spaces.
It always makes me "abc def ghi". (One space gap)
Thanks to all.

Hi,

Is this what you want: Hope this helps.

Thank you very much for trying to help me.
Here are more details on my issue.

I have a script with a variable:

msg_string='01009999888811000001E00000001000099999988881004102099999999999900__USA_________123456789 012345'

I need a code that replaces all underscores with blanks preserving the length of the message.

I ran your code and it gave me:
01009999888811000001E00000001000099999988881004102099999999999900 USA 123456789012345

As you see, we altered the message length.

Thanks again,
vouser.

Use quotes, otherwise bash interprets the spaces as argument separators.

Hi,

@MTK358: There are no spaces in the input ;)

@vouser: If you apply my solution I do think you have what you want:That is what you ask: Hope this helps.

Oh, I just got a little confused.

I would still use the braces in case the string contains bash special chars, though.

Gentlemen:

thanks for your help:

Here's my working function:

fn_send_msg(){
msg_out=`msg_get 1``msg_get 2``msg_get 3``msg_get 4``msg_get 12``msg_get 13``msg_get 14``msg_get 18``msg_get 37``msg_get 39``msg_get 59``msg_get 62`
echo "Msg before replacing:"
echo $msg_out

#msg_out=`echo $msg_out | sed 's/_/ /g'` #~ OK
msg_out="${msg_out//_/ }" #~ OK
echo "Msg out:"
echo "$msg_out"

#~ Open socket ~~~~~~~~~~~~~~~~~~~~
exec 3<>/dev/tcp/172.26.0.103/9991

#~ Send msg ~~~~~~~~~~~~~~~~~~~~~~~
echo "$msg_out" >&3

#~ Receive msg ~~~~~~~~~~~~~~~~~~~~
read -r msg_in <&3
echo "Msg in:"
echo "$msg_in" # OK
}

What I've learned is that there is a difference between:

echo $msg

and

echo "$msg"

if msg has blanks.

Regards,
vouser

since you are using bash, you can use this function to replace your strings without calling external commands.

use it like this in your script.

Bash's Parameter Expansion can do the job quite cleanly:From the link above:

${parameter/pattern/string} The pattern is expanded to produce a pattern just as in filename expansion. Parameter is expanded and the longest match of pattern against its value is replaced with string. If pattern begins with ‘/’, all matches of pattern are replaced with string. Normally only the first match is replaced.