ruario/one-shot-sftp.md

## one-shot-sftp.md

      
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              one-shot-sftp.md
            
          
    Normally if you want to quickly send a file to a remote directory on an ssh server as a one liner or within a script, the following would suffice:
scp file server:path
Occasionally, you may come across a server that only has sftp enabled and not scp. For example if the OpenSSH server you were connecting to was configured as follows:
Subsystem sftp internal-sftp

Match User yourusername
  ChrootDirectory /home/%u
  ForceCommand internal-sftp

Then attempting to connect via scp, would result in the error message: "This service allows sftp connections only."
In such a case, you can simulate basic scp behaviour as follows:
echo put file | sftp -b- server:path
Alternatively, if you need to display the progress of the file as it uploads:
printf "progress\nput file" | sftp -b- server:path
If you need to upload multiple files, you could use a for loop:
for f in file1 file2 file3; do echo put "$f" | sftp -b- server:path; done
(If this example file* would also have worked as a wildcard in place of file1 file2 file3).
You can combine all of the above to make a very simple upload script like so:
#!/bin/sh
s="$1"
shift 1
for f in "$@"; do
  printf "progress\nput $f" | sftp -b- "$s" || exit 1
done
Give this a suitable name (e.g. upload-sftp) and use it as follows:
upload-sftp server:path file*
Using Bash instead of Bourne Shell would allow you to specify server:path as the last option (like scp), i.e.:
upload-sftp file* server:path 
To do that, use the following:
#!/bin/bash
eval s=\$$#
for f in "${@:1:$(($#-1))}"; do
  printf "progress\nput $f" | sftp -b- "$s" || exit 1
done
Note: Using sftp in this way requires non-interactive authentication using keys to be configured. You can set -oBatchMode=no to use password authentication but this would be cumbersome when uploading multiple files using the above example, as you would be prompted for a password before each file is uploaded.
P.S. Yes I know the man page specifically mentions the -b switch but some basic examples help.
✍ 2022-01-17

Years later I needed something like this again. See my 'phlog' (gopher://sdf.org/1/users/r0/phlog) posts for details.

gopher://sdf.org/0/users/r0/phlog/2022-01-14_One_shot_sftp.txt
gopher://sdf.org/0/users/r0/phlog/2022-01-16_One_shot_part2.txt

Don't think you have a gopher client? You might… you can use lynx or even curl! Indeed, gopher is such a simple protocol, that if you have netcat (nc) or telnet installed, you could even hack them into fetching the content…
echo /users/r0/phlog/2022-01-14_One_shot_sftp.txt | nc sdf.org 70

(echo /users/r0/phlog/2022-01-16_One_shot_part2.txt; cat -) | telnet sdf.org 70

Alternatively, if you can't be bothered with all that or find the thought process of how I arrived at this boring, here is a summary.
#!/usr/bin/env -S bash -eu
if [ "${1:-}" = '-P' ]; then
  p="${@:1:2}"
  shift 2
fi
eval l=\${$#}
if [[ "$l" == *:* ]]; then
  for f in "${@:1:$(($#-1))}"; do
    printf '%s\n' "put ${f// /\\ }"
  done | sftp ${p:-} "$l"
else
  f="${1#*:}"
  printf '%s\n' "get ${f// /\\ } \"$2\"" | sftp ${p:-} "${1%%:*}"
fi

Limitations


You can't download multiple files like so, server:\{file1,file2\} .—I am not sure how many people knew about that scp feature anyway. You can still grab more than one file at a time using wild cards however, e.g. server:file\?.txt .
You can't download to a directory with colon in the name, or 'on-the-fly' rename a download to filename that contains a colon.
You can't rename a file on upload like so, file1 server:file2—you can still copy to an already present remote directory, e.g. file1 server:dir.
Only the -P (port) option is supported and (if you want to use it) it must be the first argument with a space to separate it from the port number.
You can't do server to server copies—another feature that might not even be widely known or used.
If certain unusual characters actually appear in filenames—and are not intended as wildcards—they would need to be double escaped (e.g. a file named file*1, would need to be uploaded as file1 server:"file\*1").