[SOLVED] /usr/local/bin in #PATH, yet command of program there does not work

mark_alfred · 04-28-2017, 09:51 AM

Hi. I'm using Ubuntu 16.04. I generally only use packages, but the older version of youtube-dl that was available in the xenial repositories was too old and did not work. So, I ported the source package from zesty to my system, and this was fine for a while. The latest available package from doing this was youtube-dl 2017.03.26-1. However, this ceased to work. I discovered that there is a more recent version of this package available, so I decided to install that (though there was not an ubuntu package available of the most recent version -- that version being 2017.04.28). The installation was done as described here, specifically with curl. This installed youtube-dl into my /usr/local/bin path. However, the command "youtube-dl" does not work. Instead, I must use the command "/usr/local/bin/youtube-dl" to get it to work. Here's a readout from "echo #PATH" command:

Code:

mark@mark-N150-N210-N220:~$ echo $PATH
/home/mark/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

So, I don't know why the "youtube-dl" command alone is not working.

Code:

mark@mark-N150-N210-N220:~$ youtube-dl
bash: /usr/bin/youtube-dl: No such file or directory
mark@mark-N150-N210-N220:~$ /usr/local/bin/youtube-dl
Usage: youtube-dl [OPTIONS] URL [URL...]

youtube-dl: error: You must provide at least one URL.
Type youtube-dl --help to see a list of all options.
mark@mark-N150-N210-N220:~$

rknichols · 04-28-2017, 10:04 AM

The most likely reason is that bash still has the old /usr/bin location in its hash table. You can see it by running "hash -l".You can clear the hash table by running "hash -r" or (easier to remember) "PATH=$PATH" since assigning to PATH also clears the hash table.

mark_alfred · 04-28-2017, 11:20 AM

Thanks rknichols. Here's what I get from the "hash -l" command. I'm not sure what exactly this means, but just in looking at it, I'm surprised that such an insignificant program as youtube-dl would be included with programs like apt or dpkg.

Code:

mark@mark-N150-N210-N220:~$ hash -l
builtin hash -p /usr/bin/dpkg dpkg
builtin hash -p /usr/bin/youtube-dl youtube-dl
builtin hash -p /usr/bin/apt apt
builtin hash -p /bin/netstat netstat
builtin hash -p /usr/bin/dpkg-buildpackage dpkg-buildpackage
builtin hash -p /usr/bin/sudo sudo
builtin hash -p /bin/mkdir mkdir
builtin hash -p /bin/ls ls
builtin hash -p /usr/bin/clear clear
mark@mark-N150-N210-N220:~$

Anyway, I ran the PATH=$PATH command, which cleared it. So, I'll see what happens... okay, the command "youtube-dl" on its own is working now.

rknichols · 04-28-2017, 12:30 PM

Quote:

Originally Posted by mark_alfred

Thanks rknichols. Here's what I get from the "hash -l" command. I'm not sure what exactly this means, but just in looking at it, I'm surprised that such an insignificant program as youtube-dl would be included with programs like apt or dpkg.

That hash table has nothing to do with "significance". Every time the shell uses $PATH to find where a command resides, it saves the result in that hash table so that it does not have to perform that search if you use that command again. The entries in that table are just the commands from $PATH directories that you have used in that shell session.