bashftp

I got bored and wrote something kinda like a single-command sftp thing in bash (BSD licensed).

It allows putting files via stdin, block by block; as well as fetching files via stdout, block by block.

The directory listing reports a readable records indicating if something is a directory or not, mtime, size, and it optionally computes md5 using the system's md5 executable.

Block transfers are handled with dd.

It is intentional to create separate connections for each transfer block, since you can retry the call a couple of times if the network is sad. It is also a spectacularily bad idea if someone's using the same files on the other end, since it will result in 100% file corruption.

You're meant to install it and use it something like:

scp bashftp.sf victim:/usr/local/bin/bashftp
ssh victim bashftp ls ~ md5
ssh victim bashftp get 0 4096 ~/thing > ~/thing
ssh victim bashftp get 4096 8192 ~/thing > ~/thing
...

There's a Makefile in there allowing you to run tests and to install it to a PREFIX (but only if you're brave).

Help output:

Usage: ./bashftp.sh [help|ls|put|get|version]
    help                  prints this message
    version               prints version
    ls path               list directory
    ls path md5           list directory and calculate md5 for files
    put start end path    receives a chunk of a file on stdin
    get start end path    returns a chunk of a file on stdout

ls format:
- directories:
      d unixtime path
- files:
      f unixtime sizeinbytes hash path
hash is 0 if not requested
Example ls output:
      d 1666266539 subdir
      f 1666266539 2279 2164e12fc5f03902b61d977fc2f29d00 file

Changelog

3.2 -> 3.3

add tree subcommand

3.1 -> 3.2

add crc32 hash type

3.0 -> 3.1

return hash 0 for files for which we get EACCESS or some other error

2.0 -> 3.0

Speed up dd by using bigger block sizes
First put block overwrites the file, but subsequent puts don't. I need to rewrite this in C and get rid of dd's 40 (or 50?) years of astonishing behaviour.

1.0 -> 2.0

put -ing files into nonexistant paths will create all intermediate paths (mkdir -p).