| README.org | ||
| vlf.el | ||
View Large Files
An Emacs mode that allows viewing, editing and searching in large files in chunks. Batch size can be adjusted on the fly and bounds the memory that is to be used for operations on the file.
This is development version of the GNU ELPA vlf.el package. Here's what it does in a nutshell:
- regular expression search on whole file (in constant memory determined by current batch size)
- chunk editing (if size has changed, saving is done in constant memory determined by current batch size)
- occur like indexing
- options to jump to beginning, end or arbitrary file chunk
- ability to jump/insert given number of batches at once
- newly added content is acknowledged if file has changed size meanwhile
- automatic scrolling of batches
- VLF is added as an option when opening large files
GNU Emacs 23 and 24 are supported.
Overview and tips
M-x vlf PATH-TO-FILE
Unicode
Emacs' Unicode support is leveraged so you'll not see bare bytes but characters decoded as if file is normally opened. This holds for editing, search and indexing.
32-bit GNU Emacs
Regular Emacs integers are used, so if you use 32-bit Emacs without bignum support and have really huge file (with size beyond the maximum integer value), VLF will probably not quite work.
Memory control
vlf-batch-size bounds the memory used for all operations.
Special mode
VLF is derived from special-mode and keeps all its properties. For example you can directly press digits to enter prefix arguments.
Change major mode
You can change major mode to whatever you like (for example hexl-mode). Saving will insert contents as intended. You can return to vlf-mode too.
Detail usage
Control batch size
+ and - control current batch size by factors of 2.
You can also set by hand local variable vlf-batch-size and then refresh with g.
Move around
M-PgUp and M-PgDn move chunk by chunk. With positive prefix argument they move prefix number of batches. With negative - append prefix number of batches.
[ and ] take you to the beginning and end of file respectively.
j jumps to given chunk. To see where you are in file and how many chunks there are (using the current batch size), look at the bracketed part of the buffer name, batch size is also there - at the end.
Search whole file
s and r search forward and backward respectively over the whole file. This is done chunk by chunk so if you have really huge file - you'd better set somewhat bigger batch size beforehand.
Occur over whole file
o builds index for given regular expression just like occur-mode. It does this chunk by chunk over the whole file. Note that even if you prematurely stop it with C-g, it will still show index of what's found so far.
Jump to line
l jumps to given line in file. This is done by searching from the beginning, so again the bigger current batch size, the quicker. With negative argument, lines are counted from the end of file.
Edit
e enters VLF in edit mode. If editing doesn't change size of the chunk, only this chunk is saved. Otherwise the remaining part of the file is adjusted chunk by chunk, so again you'd better have bigger current batch size. If chunk has been expanded the memory used is
(batch size + difference to the original chunk size) x 2