customize the cp/mv as cust_cp/cust_mv shell command to support run with test/do mode and printing the diff info.
- to run with test mode: . custcmd.sh test && [cust_cp|cust_mv] file_from file_to
- to run with do mode: . custcmd.sh do && [cust_cp|cust_mv] file_from file_to
- loaded the custcmd.sh as . custcmd.sh from your script
- then can use those commands cust_cp/cust_mv from your script
- test - just did a checking, not execute the cp/mv commands
- run - execute the cp/mv commands