Buffered files

class paramiko.file.BufferedFile

Reusable base class to implement Python-style file buffering around a simpler stream.


Returns an iterator that can be used to iterate over the lines in this file. This iterator happens to return the file itself, since a file is its own iterator.

Raises:ValueError – if the file is closed.

Close the file. Future read and write operations will fail.


Write out any data in the write buffer. This may do nothing if write buffering is not turned on.


Returns the next line from the input, or raises StopIteration when EOF is hit. Unlike Python file objects, it’s okay to mix calls to next and readline.

Raises:StopIteration – when the end of the file is reached.
Returns:a line (str) read from the file.

Read at most size bytes from the file (less if we hit the end of the file first). If the size argument is negative or omitted, read all the remaining data in the file.


'b' mode flag is ignored (self.FLAG_BINARY in self._flags), because SSH treats all files as binary, since we have no idea what encoding the file is in, or even if the file is text data.

Parameters:size (int) – maximum number of bytes to read
Returns:data read from the file (as bytes), or an empty string if EOF was encountered immediately

Check if the file can be read from.

Returns:True if the file can be read from. If False, read will raise an exception.

Read up to len(buff) bytes into bytearray buff and return the number of bytes read.

Returns:The number of bytes read.

Read one entire line from the file. A trailing newline character is kept in the string (but may be absent when a file ends with an incomplete line). If the size argument is present and non-negative, it is a maximum byte count (including the trailing newline) and an incomplete line may be returned. An empty string is returned only when EOF is encountered immediately.


Unlike stdio’s fgets, the returned string contains null characters ('\0') if they occurred in the input.

Parameters:size (int) – maximum length of returned string.
Returns:next line of the file, or an empty string if the end of the file has been reached.

If the file was opened in binary ('b') mode: bytes are returned Else: the encoding of the file is assumed to be UTF-8 and character strings (str) are returned


Read all remaining lines using readline and return them as a list. If the optional sizehint argument is present, instead of reading up to EOF, whole lines totalling approximately sizehint bytes (possibly after rounding up to an internal buffer size) are read.

Parameters:sizehint (int) – desired maximum number of bytes to read.
Returns:list of lines read from the file.
seek(offset, whence=0)

Set the file’s current position, like stdio’s fseek. Not all file objects support seeking.


If a file is opened in append mode ('a' or 'a+'), any seek operations will be undone at the next write (as the file position will move back to the end of the file).

  • offset (int) – position to move to within the file, relative to whence.
  • whence (int) – type of movement: 0 = absolute; 1 = relative to the current position; 2 = relative to the end of the file.

IOError – if the file doesn’t support random access.


Check if the file supports random access.

Returns:True if the file supports random access. If False, seek will raise an exception.

Return the file’s current position. This may not be accurate or useful if the underlying file doesn’t support random access, or was opened in append mode.

Returns:file position (number of bytes).

Check if the file can be written to.

Returns:True if the file can be written to. If False, write will raise an exception.

Write data to the file. If write buffering is on (bufsize was specified and non-zero), some or all of the data may not actually be written yet. (Use flush or close to force buffered data to be written out.)

Parameters:data (str/bytes) – data to write

Write a sequence of strings to the file. The sequence can be any iterable object producing strings, typically a list of strings. (The name is intended to match readlines; writelines does not add line separators.)

Parameters:sequence (iterable) – an iterable sequence of strings.

Identical to iter(f). This is a deprecated file interface that predates Python iterator support.