Appending text to the end of a variable

Question

The following works, but I don't want the space that it returns:

read input
file= "$input"
file= "$file ins.b" # how to get rid of the space here?
echo "$file"

This outputs 'file ins.b' I don't want the space between file and ins.b

If I don't leave that space in the code it returns only '.b'. What can I do to resolve this problem?

Review [How can I concatenate string variables in Bash](http://stackoverflow.com/questions/4181703/how-can-i-concatenate-string-variables-in-bash). It isn't quite a duplicate because it wants the space that you don't want, but some of the answers cover the cases you need covered. (For example, you could use `file="$file""ins.b"` or `file="$file"ins.b`; these are covered alternatives, as well as the simple `file="${file}ins.b"`.) — Jonathan Leffler, Jun 13 '14 at 16:40

score 4 · Accepted Answer · edited May 23 '17 at 12:27

4

Append like:

file="${file}ins.b"

If you don't use braces then it treats fileins as a variable and expands it. Since, it's probably not set it just prints .b.

edited May 23 '17 at 12:27

Community

answered Jun 13 '14 at 16:27

P.P

score 2 · Answer 2 · answered Jun 13 '14 at 16:28

2

In bash you can also reference variables like ${file}. So this should work for you:

file="${file}ins.b"

answered Jun 13 '14 at 16:28

Manny D

score 2 · Answer 3 · answered Jun 13 '14 at 16:30

2

You don't need to expand the old value at all; bash has a += operator:

file+="ins.b"

answered Jun 13 '14 at 16:30

Charles Duffy

score 1 · Answer 4 · answered Jun 13 '14 at 16:29

1

file="${file}ins.b"

or

file=$file"ins.b"

answered Jun 13 '14 at 16:29

mb14

4 Answers4