bach echo variable substitution - bash

Question

I want make a query wiht this bash code.
##fist I will extrac the table name from table.txt file
table=$(head -n 1 tables.txt)
#In this code is where I will make the substitution on the query
result=`echo "select 'result '||segment_name||':'||MB||':'||TOTAL_MB from (
select TSEG.segment_name,round(TSEG.bytes/1024/1024) MB,l.segment_name as LSEGMENT_NAME,nvl(l.MB,0) as LOB_MB,nvl(l.MB,0)+round(TSEG.bytes/1024/1024) as TOTAL_MB
from dba_segments tseg, (select LOBS.table_name,round(bseg.bytes/1024/1024) MB,lobs.SEGMENT_NAME
from dba_lobs lobs,dba_segments bseg
where LOBS.SEGMENT_NAME=bseg.segment_name
order by bseg.bytes asc
) l
where TSEG.segment_type='TABLE'
and TSEG.segment_name='$table'
and TSEG.SEGMENT_NAME=l.table_name(+)
order by TOTAL_MB
)where rownum=1;`
my problem is on line TSEG.segment_name='$table', I need the table name on format 'TABLE_NAME'.
this is my actual ouput with table named "AABLG":
select 'result '||segment_name||':'||MB||':'||TOTAL_MB from (
select TSEG.segment_name,round(TSEG.bytes/1024/1024) MB,l.segment_name as LSEGMENT_NAME,nvl(l.MB,0) as LOB_MB,nvl(l.MB,0)+round(TSEG.bytes/1024/1024) as TOTAL_MB
from dba_segments tseg, (select LOBS.table_name,round(bseg.bytes/1024/1024) MB,lobs.SEGMENT_NAME
from dba_lobs lobs,dba_segments bseg
where LOBS.SEGMENT_NAME=bseg.segment_name
order by bseg.bytes asc
) l
where TSEG.segment_type='TABLE'
' and TSEG.segment_name='AABLG
and TSEG.SEGMENT_NAME=l.table_name(+)
order by TOTAL_MB
)where rownum=1;
you can see that the " ' " is on the first position, and I don't know why.
regards.
Marco.

Answer 1

This would be much better done without echo at all. Consider, for instance:
IFS=$'\r\n ' read -r table <tables.txt
IFS= read -r -d '' result <<EOF
select 'result '||segment_name||':'||MB||':'||TOTAL_MB from (
select TSEG.segment_name,round(TSEG.bytes/1024/1024) MB,l.segment_name as LSEGMENT_NAME,nvl(l.MB,0) as LOB_MB,nvl(l.MB,0)+round(TSEG.bytes/1024/1024) as TOTAL_MB
from dba_segments tseg, (select LOBS.table_name,round(bseg.bytes/1024/1024) MB,lobs.SEGMENT_NAME
from dba_lobs lobs,dba_segments bseg
where LOBS.SEGMENT_NAME=bseg.segment_name
order by bseg.bytes asc
) l
where TSEG.segment_type='TABLE'
and TSEG.segment_name='$table'
and TSEG.SEGMENT_NAME=l.table_name(+)
order by TOTAL_MB
) where rownum=1;
EOF
This also fixes the bug observed in your question by setting IFS to a value that includes $'\r', the carriage-return character found in DOS-formatted newlines, and thus stripping such characters when they exist at the end of the first line of tables.txt.