#003 the First Line of a File
Notes
I have a text file, but the first line might need modification. What to do?
Reach for perl of course!
This requires a variation of the generic patch_file process described here.
The examples.sh script demonstrates the principle. The example is actually taking a file in Intel Hex format and pre-pending an Extended Linear Address record if one is not already present.
Example
$ ./examples.sh
Installing example.hex from template..
Original example.hex (head only)..
:10000000008000208D030000CD030000CF0300001E
:1000100000000000000000000000000000000000E0
:10002000000000000000000000000000D1030000FC
:100030000000000000000000D3030000D503000012
:10004000D7030000D7030000D7030000D703000048
:10005000D703000000000000D7030000D703000012
:10006000D7030000D7030000D7030000D703000028
:10007000D7030000D7030000D7030000D703000018
:10008000D7030000D7030000D7030000D703000008
:10009000D7030000D7030000D7030000D7030000F8
Step 1: Patching the first line (with file backup)
Cummulative diffs..
1d0
< :020000040000FA
Step 2: Try patching again - should not duplicate (without backup)
Cummulative diffs..
1d0
< :020000040000FA
Resulting example.hex (head only)..
:020000040000FA
:10000000008000208D030000CD030000CF0300001E
:1000100000000000000000000000000000000000E0
:10002000000000000000000000000000D1030000FC
:100030000000000000000000D3030000D503000012
:10004000D7030000D7030000D7030000D703000048
:10005000D703000000000000D7030000D703000012
:10006000D7030000D7030000D7030000D703000028
:10007000D7030000D7030000D7030000D703000018
:10008000D7030000D7030000D7030000D703000008
Credits and References
- How can I make changes to only the first line of a file? - SO
- Re: Replacing the first line of a text file
- The Perl Programming Language
- OSHChip/GccToolchain - where I used this recently
- Intel HEX - wikipedia