pipe - Difference between x | y and y <(x) in bash? -

is there difference between command1 | command2 , command2 <(command1)?

for example, git diff | more vs more <(git diff)

my understanding both take stdout of command2 , pipe stdin of command1.

the main difference <(...), called "process substitution", translated shell filename passed regular argument command; doesn't send command's standard input. means can't used directly commands such tr don't take filename argument:

$ tr a-z a-z <(echo hello) usage: tr [-ccsu] string1 string2        tr [-ccu] -d string1        tr [-ccu] -s string1        tr [-ccu] -ds string1 string2 

however, can put < in front of <(...) turn input redirection instead:

$ tr a-z a-z < <(echo hello) hello  

and because generates filename, can use process substitution commands take more 1 file argument:

$ diff -u <(echo $'foo\nbar\nbaz') <(echo $'foo\nbaz\nzoo') --- /dev/fd/63  2016-07-15 14:48:52.000000000 -0400 +++ /dev/fd/62  2016-07-15 14:48:52.000000000 -0400 @@ -1,3 +1,3 @@  foo -bar  baz +zoo 

the other significant difference pipe creates subshells can't have side effects in parent environment:

 $ echo hello | read x  $ echo $x  # nothing - x not set 

but process substitution, process inside parentheses in subshell; surrounding command can still have side effects:

 $ read x < <(echo hello)  $ echo $x  hello 

worth mentioning can write process >(...), although there fewer cases that's useful:

$ echo hello > >(cat) hello