Append new line to end of multiple files in linux

cd /tmp

echo “pga_aggregate_limit=0” | tee -a *.txt

execute sql command from shell in one line 

echo “drop user ABC; ” | sqlplus abc/**@db as sysdba

Search One line before and after in Grep

Get one line after grep search

oracle@server1 ~]$ lsnrctl status | grep -i Hello -A 1

Service “Hello world” has 1 instance(s).
Instance “test1”, status READY, has 1 handler(s) for this service…

grep one line before and after grep search

[oracle@server1 ~]$ lsnrctl status | grep -i Hello -B 1 -A 1

Instance “xyz”, status READY, has 1 handler(s) for this service…
Service “Hello world” has 1 instance(s).
Instance “test1”, status READY, has 1 handler(s) for this service..