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You can copy a file from the disk and insert it into a buffer
using the insert-file-contents
function. Don't use the user-level
command insert-file
in a Lisp program, as that sets the mark.
This function inserts the contents of file filename into the current buffer after point. It returns a list of the absolute file name and the length of the data inserted. An error is signaled if filename is not the name of a file that can be read.
The function
insert-file-contents
checks the file contents against the defined file formats, and converts the file contents if appropriate. See Format Conversion. It also calls the functions in the listafter-insert-file-functions
; see Saving Properties. Normally, one of the functions in theafter-insert-file-functions
list determines the coding system (see Coding Systems) used for decoding the file's contents.If visit is non-
nil
, this function additionally marks the buffer as unmodified and sets up various fields in the buffer so that it is visiting the file filename: these include the buffer's visited file name and its last save file modtime. This feature is used byfind-file-noselect
and you probably should not use it yourself.If beg and end are non-
nil
, they should be integers specifying the portion of the file to insert. In this case, visit must benil
. For example,(insert-file-contents filename nil 0 500)inserts the first 500 characters of a file.
If the argument replace is non-
nil
, it means to replace the contents of the buffer (actually, just the accessible portion) with the contents of the file. This is better than simply deleting the buffer contents and inserting the whole file, because (1) it preserves some marker positions and (2) it puts less data in the undo list.It is possible to read a special file (such as a FIFO or an I/O device) with
insert-file-contents
, as long as replace and visit arenil
.
This function works like
insert-file-contents
except that it does not do format decoding (see Format Conversion), does not do character code conversion (see Coding Systems), does not runfind-file-hooks
, does not perform automatic uncompression, and so on.
If you want to pass a file name to another process so that another
program can read the file, use the function file-local-copy
; see
Magic File Names.