OS X pipeline command not found

I had this problem using bash on my MacBook with OS X. Pipes didn’t work any more. A command like

$ ls | wc


would give me the response

-bash:  wc: command not found


I thought I’d lost the wc command.  But locate found it. I checked my PATH. It was correct. Then I found that many other commands wouldn’t work. Even less didn’t work.  However, if I used the lost command without a pipe, e.g.:

$ wc *.js


then it would be found.

What was going on?

Eventually in desperation I copied the command and pasted it into a text file, then ran od on it.

$ od -bc x
0000000   154 163 040 174 302 240 167 143 012
__________ l   s       |      **   w   c  \n
0000012

And there I found the culprit.

After the vertical bar pipe symbol I expected to see octal 040, the code for a space. That’s what you see before the pipe symbol. But what I saw here was 302 followed by 240, i.e. two bytes, not one. “302 240” is a UTF-8 encoded string (C2 A0) for Unicode code point A0 and represents a non breaking space character.

The cause?

I have a German keyboard. To get a pipe symbol ‘|‘ I have to hold down the [alt]-key and press the 7-key (Shift-7 is forward-slash ‘/’). When I then typed the space after the pipe, I wasn’t letting go of the [alt]-key fast enough, so I was typing [alt]-space instead of a regular space. Bash interpreted the non-whitespace [alt]-space character as part of the command name, and couldn’t find anything to match.  If I let go of the [alt]-key before typing the space, all was well.

It turns out that you can make bash interpret the non breaking space as a regular space. Just add the following lines to ~/.inputrc:


# Map (UTF-8) non-breaking space to regular space,
# in case the user accidentally types Option-Space
# or [alt]-Space when they meant Space.
"\xC2\xA0": " "


Thanks to Xtra Crispy at https://discussions.apple.com/ for that tip.

I hope you find this before you waste as much time as I did trying to find out what was going wrong. Have fun bashing.