Piping commands after a piped xargs
You are almost there. In your last command, you can use -I
to do the ls
correctly
-I replace-str
Replace occurrences of replace-str in the initial-arguments with names read from standard input. Also, unquoted blanks do not terminate input items; instead the separator is the newline character. Implies
-x
and-L 1
.
So, with
find . -type d -name "*log*" | xargs -I {} sh -c "echo {}; ls -la {} | tail -2"
you will echo
the dir found by find
, then do the ls | tail
on it.
GNU Parallel makes this kind of tasks easy:
find . -type d -name "*log*" | parallel --tag "ls -la {} | tail -2"
If you do not want to do a full install of GNU Parallel you can do a minimal installation: http://git.savannah.gnu.org/cgit/parallel.git/tree/README
Just in addition to fredtantini and as a general clarification (since the docs are a bit confusing):
The xargs -I {}
will take the '{}' characters from the standard input and replace them with whatever comes in from the pipe. This means you could actually replace {}
with any character combination (maybe to better suite your preferred programming flavor). For example: xargs -I % sh -c "echo %"
. If you always use the xargs -I {}
you can replace it with xargs -i
as it is the shorthand. EDIT: The xargs -i
option has been deprecated, so stick to the xargs -I{}
.
The sh -c
will tell your bash/shell to read the next command from a string and not from the standard input. So writing sh -c "echo something"
is equivalent to echo something
.
The xargs -I {} sh -c "echo {}"
will read the input you created with sh -c
which is echo {}
. Since you told it to replace {}
with the arguments you got from the pipe, that's what will happen.
You can easily test this even without piping, just type the above command in a terminal. Whatever you write next will get outputted to the terminal (Ctrl-D to exit).
In the ls -la {}
command the same thing happens again. The {}
is replaced with the contents of the pre-pipe command.