sync only one folder on linux

Nothing new, but SSDs smaller than Dropbox storage.

Because the filesystem is out of space, i excluded a large number of files from syncing locally to dropbox using

dropbox exclude add ~/Dropbo/ExcludeThisLargeFolder/

But dropbox does not free up that space first, it continues to attempt to download more files even though it knows it is out of space.

Does not matter if i 'Pause Syncing' or limit the download bandwidth to about zero.

Need exclude to go first.
Not sure if the Delete operation talked about above applies to files and folders you do NOT want deleted from Dropbox.com storage.

i just happened to find this old bash script i wrote under ~/Dropbox/.dropbox.cache/old_files/

Because it was found under /old_files/, it is probably not the best version, so use at your own risk!  Since it does not delete files, only does dropbox exclude operations, it might be safe.  This was written maybe a decade ago.  

Looks like it would give an error because a folder does not exist in the readlink call.  mkdir -p ${T} before looping might be necessary. 

The intent is to automate adding a parent folder of the deeply nested targeted folder folder you want to download. 

While excluding all other folders brought in when a parent folder is added. 

I should have a newer version in my old bitbucket files or github or sf, but will take a while to find it.

#!/bin/bash
echo Problems:
echo dropbox exclude remove ~/Dropbox/DontExcludeMe/MeNeither
echo does nothing unless its parent directory is first included first.
echo When the parent directory is included, it brings in all its subfolders and files. 
echo I smell a tree walk of some kind here.  
echo Is bash capable of binary trees?

echo Would have to include all the ancestors that do not exist yet
echo and then add the child directories one-at-a-time
echo but at the same time, exclude any other directories.  

D=~/Dropbox
T=~/Dropbox/DontExcludeMe/MeNeither   # T for TARGET
#mkdir -p ${T}   # May need to uncomment this to precreate the wanted nested folder.
T2=${T}; 

dropbox exclude remove ${T}  #WONT DO ANYTHING IF PARENT DOES NOT EXIST.
echo ${T2}; 
while [ ${D} != ${T2} ]; do J=$(dirname $(readlink -f ${T2} ));  #readlink CAUSES FAILURE WHEN $T DOES NOT EXIST
	echo readlink CAUSES FAILURE WHEN ${T2} DOES NOT EXIST.  Add code to test for existance of ${T2}.
	echo ${J}; 
	echo "We have to filter for the directory target ${T2}, otherwise we add it right back to be excluded!"
	dropbox exclude remove ${T2}  
	sync   #Give it a little time to come back.  Should loop for it to be back in existence.
	find ${T2} -maxdepth 1 -type d -print0 | egrep -v "^${T2}$" | xargs -0 dropbox exclude add
	T2=$J; 
done;

#find ${T} -maxdepth 1 -type d -print0 | egrep -v "^${T}$" | xargs -0 dropbox exclude add 

Hi Robert T.26,

There are some missing features in Dropbox for Linux and there is no way this BUG to be compensated. For simplifying exclusion of everything else (as much as possible), but a desired folder, you can use following script:

#!/bin/bash
##############################################################################
#                    Minimize local folders in sync
#                    ------------------------------
# Evaluation is performed based on passed folder that has to stay local.
# Other files/folders get keep if/when needed only.
# Verified on Dropbox v170.4.5895
# Just make it executable (if need, using
#   $ chmod a+x stayAloneInDropbox
# ) and run it.
# Author: Здравко
#   www.dropboxforum.com/t5/user/viewprofilepage/user-id/422790
##############################################################################

# General command line check.
errorMesage() {
  echo "Command line should be 'stayAloneInDropbox <folder in Dropbox>'"
  echo "  where <folder in Dropbox> should be a folder you want to stay in"
  echo "  local Dropbox folder as is comletely, but everything else limited"
  echo "  as much as possible."
  echo
  echo "$@"
  exit 1
}
if [ $# -ne 1 ]
then
  errorMesage "Expected arguments count 1, provided $# -> $@"
fi
target_folder=`realpath "$1"`
EOL=$'\n'

##############################################################################
# Command argument validation.
if [ ! -d "$target_folder" ]
then
  errorMesage "😯 The argument ($1) does NOT point a folder."
fi

##############################################################################
# Figuring out local Dropbox folder location.
dbx_dir=`jq -r .personal.path ~/.dropbox/info.json`
if [ $? -ne 0 ]
then
  echo "Cannot detect Dropbox application installed and worked local."
  exit 1
fi
if [ ! -d "$dbx_dir" ]
then
  echo "Incorrect Dropbox folder path ($dbx_dir)!"
  echo "Only individual Dropbox account is supported."
  exit 1
fi

##############################################################################
# Dropbox folder validation.
if [[ "${target_folder:0:${#dbx_dir}}" != "$dbx_dir" ]]
then
  errorMesage "🤦 The pointed folder ($1) does NOT reside within your${EOL}\
Dropbox folder ($dbx_dir)."
fi
if [[ "$target_folder" == "$dbx_dir" ]]
then
  errorMesage "Nothing to do. Dropbox folder itself is always there!${EOL}\
Point some subfolder there."
fi

##############################################################################
# Process nested folders.
while [[ "$target_folder" != "$dbx_dir" ]]
do
  parent_folder=`dirname "$target_folder"`
  template=`basename "$target_folder"`
  echo
  echo "Keep only subfolder '$template' and remove all others"
  echo "in the folder '$parent_folder'..."
  template="/$template"
  if [[ "$parent_folder" == "$dbx_dir" ]]
  then
    template="${template}|/.dropbox.cache"
  fi
  find "$parent_folder" -mindepth 1 -maxdepth 1 -type d -print0 | \
    egrep -z -v "($template)\$" | xargs -0 dropbox exclude add
  target_folder="$parent_folder"
done

echo
echo "Complete! 😉"
echo

Take in mind that it wont fix any existing issue, but just simplifying the exclusion process. 🤷 Bugs can be fixed by Dropbox developers only.

Hope this helps to some extent. 😉