-# travelrc
+# travelrc – take your rc-files with you when using ssh or su
-take your rc-files with you when using ssh or su
\ No newline at end of file
+ ## What is the problem?
+
+Over the years, I massively configure commandline tools that I regularly use, like bash, vim, screen an so on.
+I created aliases, a custom prompt, special keybindings and commands.
+It fits my workflow very well.
+But every time I switch to another system (ssh to a local VM, or cloud-VM, or a docker container; changing to root) none of these settings work anymore and I'm annoyed.
+
+## How can it be solved?
+
+I put my rc-files in a git repo and cloned it on systems that I use regularly.
+It works, I just have to pull my latest changes a lot.
+But it does not work on temporal systems or on systems where I do not want to clone (or can't clone) all my rc-files.
+The requirements that I came up with for traveling with my rc-files are like this:
+
+* only save travelled rc-files temporarily
+* it's okay to travel with just the most important rc-files
+* do not interfere with already existing rc-files (especially for shared accounts like root)
+* use it with ssh, su (changing to root or another user on the same machine), docker, and probably more
+* do not add too much steps in the process (no rollout via ansible, no scp then ssh), keep it ephemeral
+
+## How did I solve it?
+
+I searched the internet for solutions to my problem, found something (https://github.com/IngoMeyer441/sshrc) and extended and (in my opinion) improved it.
+
+The basic idea is to minify (remove comments), compress and tar the rc-files,
+convert this archive to a (long) string (base64 encode),
+and add this string and commands to decompress and extract it as a command to ssh (or su/docker).
+
+My solution requires some steps which I'll outline here.
+It can be used as is, but it can also act as an inspiration for other solutions.
+
+* create a directory (the name of the directory is used once in the ```minify-trc``` function below) and symlink (or copy) the rc-files, that should travel with you, into it
+
+```
+mkdir $HOME/.travelrc
+ln -s -t $HOME/.travelrc $HOME/{.bashrc,.inputrc,.vimrc,.screenrc,.tmux.conf}
+```
+
+* add a directory with executables that should be available in the travelled session
+
+```
+mkdir $HOME/.travelrc/trcbin
+echo '#!/bin/bash
+bash --rcfile "$TBASHRC"' > $HOME/.travelrc/trcbin/trcbash
+chmod +x $HOME/.travelrc/trcbin/trcbash
+```
+
+* add helper functions to your ```.bashrc```
+
+```
+minify-trc() {
+ # this function copies the trc files to a tempdir and minifies them, it returns the tempdirname on stdout
+ local trcdir="${TRAVELRCDIR:-$HOME/.travelrc}" # use the travelled rc dir if already travelled
+ [ -f "$trcdir/.bashrc" ] || { echo "file .bashrc inside trcdir \"$trcdir\" does not exist" >&2; return 1; }
+ # remove all comments from the files to decrease size, has to be done carefully (comment characters can be inside quotes or other commands)
+ echo -n "minifying trcdir... " >&2
+ local trc_min_dir="$(mktemp --directory "/tmp/.trc.min.XXXXXX")"
+ cp --dereference --recursive --target-directory="$trc_min_dir" "$trcdir/"*
+ [ -f "$trc_min_dir/.vimrc" ] && sed --in-place -e 's/^ *".*$//' -e 's/ \+" .*$//' "$trc_min_dir/.vimrc" # special minifyer for vimrc
+ find "$trc_min_dir/" -type f -exec sed --in-place -e 's/^ *#[^!].*$//' -e 's/ \+# .*$//' '{}' '+' # minify all files as if they were shell scripts
+ echo "$trc_min_dir"
+}
+
+trccmd() {
+ # echo all the commands to travel with rc files, arguments act as additional arguments to tar
+ local trc_min_dir="$(minify-trc)"
+ echo -n "packing trcdir... " >&2
+ local trcvar="$(tar --create --file=- "$@" --directory="$trc_min_dir" --dereference ./ | base64 --wrap=0)" # this writes the compressed contents of $trc_min_dir base64-encoded to $trcvar
+ rm -rf "$trc_min_dir" # delete the temporal directory generated by minify-trc
+ echo "to ${#trcvar} bytes... " >&2
+ [ ${#trcvar} -lt 65536 ] || { echo "content of trcdir \"$trcdir\" is too big, even after minifying" >&2; return 1; }
+ # export $TRAVELRCDIR and create this directory, it could also be created in /tmp
+ echo '
+export TRAVELRCDIR=$HOME/.travelrc.travelled
+readonly TRAVELRCDIR
+mkdir --parents $TRAVELRCDIR
+'
+ # SSH_TTY should still be set to figure out whether this is a ssh session
+ [ -z "$SSH_TTY" ] || echo "export SSH_TTY=$SSH_TTY"
+ # decompress the files saved to $trcvar; start a bash with the travelled rc-file; only remove $TRAVELRCDIR if there is no screen or tmux session (which can still use the files); last command is true so that the returncode is always 0
+ # TODO: is it save to always remove $TRAVELRCDIR because it will be recreated on the next connection?
+ echo '
+echo '"$trcvar"' | base64 --decode | tar --file=- --extract '"$@"' --touch --directory=$TRAVELRCDIR
+chmod --quiet --recursive go= $TRAVELRCDIR
+bash --rcfile $TRAVELRCDIR/.bashrc
+screen -ls 1>/dev/null 2>&1 || tmux has-session 1>/dev/null 2>&1 || rm -rf $TRAVELRCDIR
+true
+'
+}
+```
+
+* add functions to your ```.bashrc``` that enable travelling with the rc files via ssh, su, and docker
+ * I prepended a „t“ to each of these commands, so when I type ```ssh host``` and realize that my rc-files are missing, I can disconnect, prepend a „t“ tho the previous command (to get ```tssh host```) and everything is better :-)
+ * this code has to be added after the helper functions mentioned above
+
+```
+tssh() {
+ # use -t to force the allocation of a terminal
+ ssh -t "$@" "$(trccmd --xz)"
+}
+complete -F _ssh tssh # this is the same as for ssh; function _ssh might not exist when this is called, but will be created automagically when requesting completion for ssh
+
+tdocker() {
+ local dcmd="$1"
+ shift
+ # some docker images don't come with --xz support, so --gzip is used
+ docker "$dcmd" --interactive --tty "$@" bash -c "$(trccmd --gzip)"
+}
+# TODO: add completion
+
+tsu() { # travel substitude user
+ local next_user="${1:-root}"
+ local tsu_cmd="$(mktemp "/tmp/.tsu-cmd.XXXXXX")"
+ # create a script as tsu_cmd, which should always return 0 to be able to tell whether tsu was successful
+ trccmd --gzip > "$tsu_cmd"
+ chmod --quiet ugo=rx "$tsu_cmd"
+ # try several ways to change the user and execute the tsu_cmd
+ local tsu_done="false"
+ if type -P sudo &>/dev/null; then
+ # the groups test might not be very accurate, but it is quiet; sudo is usually allowed for user vagrant
+ # the sudo test is accurate, but creates log messages, which might not be desired, especially when sudo is not allowed
+ if groups | \grep --quiet -e "sudo" -e "admin" -e "wheel" || [ "$USER" = "vagrant" ] #\
+ #|| \sudo -nv &>/dev/null || \sudo -nv 2>&1 | \grep --quiet '^sudo:' # sudo is allowed with or without password
+ then
+ echo "trying sudo, enter your password:"
+ # 'sudo -u' seems better than 'sudo su' because the latter displayed problems with IOCTL (I/O-Control)
+ sudo -u "$next_user" "$tsu_cmd" && tsu_done="true"
+ #sudo su "$next_user" --command "$tsu_cmd" && tsu_done="true"
+ else
+ read -p "sudo might not be allowed for you ($USER), try anyway? [y/N] " try_sudo_anyway
+ [ "y" = "$try_sudo_anyway" ] && sudo -u "$next_user" "$tsu_cmd" && tsu_done="true"
+ fi
+ if ! "$tsu_done" && [ "$next_user" != "root" ]; then
+ echo "trying su 'root' to call sudo '$next_user', enter root's password:"
+ su "root" --command "sudo -u $next_user $tsu_cmd" && tsu_done="true"
+ fi
+ fi
+ if ! "$tsu_done"; then
+ echo "trying su '$next_user', enter $next_user's password:"
+ su "$next_user" --command "$tsu_cmd" && tsu_done="true"
+ fi
+ if ! "$tsu_done"; then
+ echo "trying su 'root' --command su '$next_user', enter root's password:"
+ su "root" --command "su $next_user --command '$tsu_cmd'" && tsu_done="true"
+ fi
+ $tsu_done || echo "sorry, tsu did not work in this case :-("
+ rm --force "$tsu_cmd"
+}
+complete -A user tsu # complete usernames
+```
+
+* add code to your ```.bashrc``` (the one that will travel) to detect whether this is a „travelled rc session“ and make some configurations, i.e. make screen and vim use the travelled rc-files, and add the „trcbin“ directory to PATH
+ * I have this at the beginning of my ```.bashrc```, but _after_ defaults for ```EDITOR``` and ```INPUTRC``` have been set
+
+```
+if [ -n "$TRAVELRCDIR" ]; then # this is a travelled rc session
+ [ -f "$TRAVELRCDIR/.bashrc" ] && export TBASHRC="$TRAVELRCDIR/.bashrc"
+ [ -f "$TRAVELRCDIR/.inputrc" ] && export INPUTRC="$TRAVELRCDIR/.inputrc"
+ [ -f "$TRAVELRCDIR/.screenrc" ] && type -P screen &>/dev/null && alias screen="$(type -P screen) -c $TRAVELRCDIR/.screenrc -s trcbash"
+ [ -f "$TRAVELRCDIR/.tmux.conf" ] && type -P tmux &>/dev/null && alias ttmux="$(type -P tmux) -f $TRAVELRCDIR/.tmux.conf new-session 'trcbash'" # this alias does not work properly when named "tmux" (it fucked up other calls of tmux)
+ if [ -f "$TRAVELRCDIR/.vimrc" ] && type -P vim &>/dev/null; then
+ export EDITOR="$(type -P vim) -u $TRAVELRCDIR/.vimrc"
+ alias vim="$EDITOR"
+ fi
+ [ -d "$TRAVELRCDIR/trcbin" ] && export PATH="$TRAVELRCDIR/trcbin:$PATH" # add (prepend) trcbin to PATH
+fi
+```
+
+## FAQ
+
+* Can it fix more problems?
+ * yes, you can add more executables to PATH
+ * I had to execute scripts that unnecessarily used ```clear```, which meant that I was not able to scroll up anymore, so I added a script to the ```trcbin``` directory with the name ```clear```, but which did not do a real clear → problem solved (for me)
+* Can it be used with zsh?
+ * most likely yes, just replace bash with zsh, but zsh might not be installed on the destination-system and then you're screwed; perhaps bash works with most of the zsh configurations, I can't tell
+* Is it very efficient?
+ * probably not :-(
+ * I've tried to make it efficient, but I think in some cases it starts much more shells then necessary (i.e. ```trcbash``` in the ```trcbin``` directory)
+ * it might slow down ssh connections a few seconds, but for me having my rc-files with me outweighs this downside
+* Does it work with tmux?
+ * not very well (see the ttmux alias above), but when tmux is started (or a new window is created), just type ```trcbash``` and you'll get a proper bash ;-)
+* Is this project finished?
+ * I've been using it for around a year now and am still improving if necessary
projects / travelrc.git / commitdiff