Overwriting a portion of a text file without reading the entire file

[wiebe@CARYA]

---

@SolPS wrote:

Hi Altenbach,

Thanks for your reply. The file will be accumulating data over time and get very large. That was why I wanted to see if I could avoid having to read the entire file. 

---

If you're just adding data, why read the file at all?

Just open the file (or keep an open reference), move the position to the end (if you just opened the file), write data....

[altenbach]

---

wiebe@CARYA wrote:

---

@SolPS wrote:

Hi Altenbach,

Thanks for your reply. The file will be accumulating data over time and get very large. That was why I wanted to see if I could avoid having to read the entire file. 

---

If you're just adding data, why read the file at all?

Just open the file (or keep an open reference), move the position to the end (if you just opened the file), write data....

---

My understanding of the problem was that the file is ultimately very large, but they want to change the header (i.e. the beginning of the file) at any time. Of course it does sound a bit weird why that would be needed. 😮

[SolPS]

I need to edit parts of the header in the data log file each time a new data set is appended to the existing file. The new data addition can occur over a period of several days during which time, the amount of data in the file would have become considerably large.

[wiebe@CARYA]

---

@SolPS wrote:

I need to edit parts of the header in the data log file each time a new data set is appended to the existing file. The new data addition can occur over a period of several days during which time, the amount of data in the file would have become considerably large.

---

OK, but that's covered now, right?

☑️ Reading (just) the header is no problem...

☑️ Modifying the header is no problem (as long as the size doesn't grow)

☑️ Adding data isn't a problem.