Space Stalker in SQL Output

Why would a psql statement insert a leading space into the output, which
is a single integer value?

The leading space caused my job call to fail elsewhere in the same shell
script as the psql call. Here is the anonymized version of the psql
call to assign a value to a shell script variable:

IDz=`psql -d proddb -U produser -h 10.9.999.99 -p 99900 -t <
last_id.sql`

The output is simply a max(id) value, which is defined as an integer
data type in the source table column. The output looked like this
(notice the leading space before the integer value):

echo “IDz =${IDz}
IDz =’ 100’

The last_id.sql itself is simply: select max(id) from prodtable;

I'm using:

PostgreSQL 9.5.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7
20120313 (Red Hat 4.4.7-16), 64-bit

I fixed the output in the shell script with a tr command but why should
that be necessary? What is causing the space to be prepended to integer
value?

ID=`echo ${IDz} | tr -d ''`
IDz =’100’

Knowing the root cause of the space stalker would be most helpful.
Thanks for your help!

Sue

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Susan E Hurst
Principal Consultant
Brookhurst Data LLC
Email: susan(dot)hurst(at)brookhurstdata(dot)com
Mobile: 314-486-3261