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GNU Emacs
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32.9 Unset PWD Before Using Emacs

I've seen a number of strange situations in which Emacs can't find files unless you type a complete ("absolute") pathname (1.21), starting from the root (/ ). When you try to "visit" a file, you'll get the message File not found and directory doesn't exist.

In my experience, this usually means that the C shell's PWD environment variable (6.3) has gotten set incorrectly. There are a few (relatively pathological) ways of tricking the C shell into making a mistake. More commonly though, I've seen a few systems on which the C shell sticks an extra slash into PWD: that is, its value will be something like /home/mike//Mail rather than /home/mike/Mail. UNIX doesn't care; it lets you stack up extra slashes without trouble. But Emacs interprets // as the root directory - that is, it discards everything to the left of the double slash. So if you're trying to edit the file /home/mike//Mail/output.txt, Emacs will look for /Mail/output.txt. Even if this file exists, it's not what you want. [This also happens when Emacs is called from a (Bourne) shell script that has changed its current directory without changing PWD. -JP ]

This problem is particularly annoying because the shell will automatically reset PWD every time you change directories - so the obvious solution, sticking unsetenv PWD in your .cshrc file, doesn't do any good.

What will work is defining an alias (10.1):

alias gmacs "(unsetenv PWD; emacs \!*)"

A better solution might be to switch to another shell that doesn't have this problem. The Bourne shell (sh) obviously doesn't, since it doesn't keep track of your current directory.

- ML

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