facing issue while populating/referencing the variable in shell I have an input file which has data as shown below: name,local_unit,region_unit AAAAA,hour,cell BBBBB,15min,cell Here is my shell #!/bin/bash file_path='/home/vikrant_singh_rana/test_bq_file.csv' { read while IFS=, read -r name local_unit region_unit do echo $name echo $local_unit echo $region_unit ingest_tablename=ABC_XYZ_$name echo $ingest_tablename aggr_tablename=ABC_XYZ_$name_$local_unit_$region_unit_aggregation echo $aggr_tablename done } < $file_path It is able to populate the table name for variable `ingest_tablename` and not for `aggr_tablename` Output as shown below: AAAAA hour cell ABC_XYZ_AAAAA ABC_XYZ_ BBBBB 15min cell ABC_XYZ_BBBB ABC_XYZ_

Because the underline `_` is a valid character in variable names, `ABC_XYZ_$name_$local_unit_$region_unit_aggregation` tries to expand variables called `$name_`, `$local_unit_` and `$region_unit_aggregation`. The first two are probably wrong. To stop that, put the variable names in question in braces, i.e.


aggr_tablename="ABC_XYZ_${name}_${local_unit}_$region_unit_aggregation"


(or `aggr_tablename="ABC_XYZ_${name}_${local_unit}_${region_unit}_aggregation"` if that's what it should be.)

The quotes aren't strictly necessary in the assignment but otherwise a good idea.

FWIW, shellcheck.net tells of the problem, but sadly not how to solve it, it says:

> ^-- SC2154: name_ is referenced but not assigned (did you mean 'name'?).