Ubuntu – Command “find -name” must be enclosed in quotes or it doesn’t work. Why is that

command linefind

find . -name *.rb

doesn't work on my ubuntu

I have to do

find . -name "*.rb"

to get it to work.

Why is that?

Best Answer

If you have a file in the current directory ending with .rb, it'll be expanded by the shell. So, if you have one file named "foo.rb", the command that gets executed is find . -name foo.rb. ("find a file named foo.rb")

It gets even worse if you've multiple files in the current directory (say, "foo.rb" and "bar.rb"). Then the command becomes find . -name foo.rb bar.rb, which will cause an argument error for find.

To prevent the shell from expaning the glob pattern *.rb, you must either quote it (either single or double quotes will do) or escape the asterisk. The below commands have equivalent behavior:

find . -name "*.rb"
find . -name '*.rb'
find . -name \*.rb

Related Solutions

Find File by Name – How to Locate a File Using Command-Line

Try find ~/ -type f -name "postgis-2.0.0" instead.

Using . will only search the current directory. ~/ will search your entire home directory (likely where you downloaded it to). If you used wget as root, its possible it could be somewhere else so you could use / to search the whole filesystem.

Goodluck

Ubuntu – Why doesn’t the command “ls | file” work

The fundamental issue is that file expects file names as command-line arguments, not on stdin. When you write ls | file the output of ls is being passed as input to file. Not as arguments, as input.

What's the difference?

Command-line arguments are when you write flags and file names after a command, as in cmd arg1 arg2 arg3. In shell scripts these arguments are available as the variables $1, $2, $3, etc. In C you'd access them via the char **argv and int argc arguments to main().
Standard input, stdin, is a stream of data. Some programs like cat or wc read from stdin when they're not given any command-line arguments. In a shell script you can use read to get a single line of input. In C you can use scanf() or getchar(), among various options.

file does not normally read from stdin. It expects at least one file name to be passed as an argument. That's why it prints out usage when you write ls | file, because you didn't pass an argument.

You could use xargs to convert stdin into arguments, as in ls | xargs file. Still, as terdon mentions, parsing ls is a bad idea. The most direct way to do this is simply:

file *

Best Answer

Related Solutions

Find File by Name – How to Locate a File Using Command-Line

Ubuntu – Why doesn’t the command “ls | file” work

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