When working on update target field in Cassandra in batch, the IN operator is
used with comma separated primary keys.
To get a list of primary keys is simple, for example, you can CAPTURE them
to a text file and find them out by bash pipeline if needed, then we need to put
them into a single line with comma as separator.
For example, the file test.txt conatins primary keys:
1 | aaaaa |
There are multi-way to do it, one is using paste command:
1 | cat test.txt | paste -s -d, - |
The output is:
1 | aaaaa,bbbbb,ccccc,ddddd |
Using tr command can do the same with an additional tail comma, for example:
1 | cat test.txt | tr '\n' ',' |