xargs with command that open editor leaves shell in weird state

Using the simpler example of

ls *.h | xargs vim

here are a few ways to fix the problem:

xargs -a <( ls *.h ) vim

or

vim $( ls *.h | xargs )

or

ls *.h | xargs -o vim

The first example uses the xargs -a (--arg-file) flag which tells xargs to take its input from a file rather than standard input. The file we give it in this case is a bash process substitution rather than a regular file.

Process substitution takes the output of the command contained in <( ) places it in a filedescriptor and then substitutes the filedescriptor, in this case the substituted command would be something like xargs -a /dev/fd/63 vim.

The second command uses command substitution, the commands are executed in a subshell, and their stdout data is substituted.

The third command uses the xargs --open-tty (-o) flag, which the man page describes thusly:

Reopen stdin as /dev/tty in the child process before executing the command. This is useful if you want xargs to run an interactive application.

If you do use it the old way and want to get your terminal to behave again you can use the reset command.

The problem is that since you're running xargs (and hence git and hence vim) in a pipeline, its stdin is taken from the output of cat projectPaths rather than the terminal; this is confusing vim. Fortunately, the solution is simple: add the -o flag to xargs, and it'll start git (and hence vim) with input from /dev/tty, instead of its own stdin.

The man page for GNU xargs shows a similar command for emacs:

xargs sh -c 'emacs "$@" < /dev/tty' emacs

(in this command, the second "emacs" is the "dummy string" that wisbucky refers to in a comment to this answer)

and says this:

   Launches  the  minimum  number of copies of Emacs needed, one after the   other, to edit the files listed on xargs' standard input.  This example   achieves the same effect as BSD's -o option, but in a more flexible and   portable way.

Another thing to try is using -a instead of cat:

xargs -a projectPaths -I project git --git-dir=project/.git --work-tree=project commit -a

or some combination of the two.