Re: Removing newline \n embedded by regex

[Greg Wooledge]

On Tue, Sep 07, 2021 at 05:50:34AM +0300, Tapani Tarvainen wrote:
> On Tue, Sep 07, 2021 at 02:35:59AM +0000, Budi (budikusasi@gmail.com) wrote:
> 
> > How do we remove newline \n embedded on end of a string by use of bash regex
> 
> var="${var%
> }"
> 
> or
> 
> var="${var%'$\n'}"
> 
> or
> 
> var="${var%'$\012'}"
> 
> or
> 
> var="${var%'$\x0A'}"

Note: none of these involves the use of a "regex".  Parameter expansion
with the % modifier involves a glob-style pattern match.  And in this
particular case, the pattern is actually a single-character constant
string.

A better question is: why does your string have a newline at the end of
it?  How did you get this value into the string in the first place?

If you used read, the delimiter (newline by default) is automatically
stripped for you.

If you used mapfile (readarray), you can use the -t option to strip
the trailing newlines from each input line.