GIT : "git-upload-pack: command not found" while pushing to remote server

If you can not adjust the effective PATH on the remote side¹, then you will have to specify the location of the programs from your local side.

As you found, git clone can be given -u /path/to/git-upload-pack (or --upload-pack /path/to/git-upload-pack).

git fetch and git pull accept --upload-pack /path/to/git-upload-pack (not -u, however, since it means something else to these programs). They also check the remote.<name>.uploadpack configuration variable.

git push accepts --receive-pack /path/to/git-receive-pack and checks the remote.<name>.receivepack configuration variable.

Once you have your repository cloned, you can use the configuration variables to record the paths:

git clone -u /home/bin/git-upload-pack user@server.com:mygitfoldercd mygitfoldergit config remote.origin.uploadpack /home/bin/git-upload-packgit config remote.origin.receivepack /home/bin/git-receive-pack

Then you can push, fetch, or pull without having to specify the path.

¹You said that “environment variables [are] blocked for SSH accounts”. If you mean that the sshd has its PermitUserEnvironment setting turned off (meaning that you can not use environment="PATH=/home/bin:/usr/bin:/bin" in your .ssh/authorized_keys file), then you still might be able to modify your default PATH via a shell initialization file (e.g. .bashrc).