Sometimes commands repeat in pipeline command. For example (just to illustrate):
$ grep -lF 'pattern' ./foo/**/*.bar | xargs dirname | xargs dirname
Is there a way to shorten chaining command? For example, I have a command:
$ ... | some-command | some-command | some-command | ...
I'd like to get same result with something like to the following
$ ... | (some-command) ^ 3 | ...
Of course, it wouldn't work, but it illustrates what I'd like to make.
Recursion + evil:
repiper() {
local -i n="$1";
shift;
if (( n )); then
eval "$@" | repiper $((n-1)) "$@";
else
eval "$@";
fi
}
$ grep -lRF function dev/jquery/build | repiper 3 xargs -n1 dirname | head
.
.
dev
dev
dev
dev
$ grep -lRF function dev/jquery/build | repiper 1 xargs -n1 dirname | head
dev/jquery
dev/jquery
dev/jquery/build
dev/jquery/build
dev/jquery/build
dev/jquery/build
$ grep -lRF function dev/jquery/build | repiper 0 xargs -n1 dirname | head
dev/jquery/build
dev/jquery/build
dev/jquery/build/tasks
dev/jquery/build/tasks
dev/jquery/build/tasks
dev/jquery/build/tasks
Not beautiful but I believe you can do what you want using a while and a for loop.
$ seq 5 | while read -r f; do for i in {1..3}; do echo "[$i]: blah $f";done; done
[1]: blah 1
[2]: blah 1
[3]: blah 1
[1]: blah 2
[2]: blah 2
[3]: blah 2
[1]: blah 3
[2]: blah 3
[3]: blah 3
[1]: blah 4
[2]: blah 4
[3]: blah 4
[1]: blah 5
[2]: blah 5
[3]: blah 5
Here's the construct broken out:
$ <CMD> | while read -r f; do
for i in <range>; do
...do command some num. of times...
done
done
The other way to view this would be to create a shell function (function () {...}) and call that instead of xargs ... multiple times. This function coud take 2 arguments, a number of times to run argument, and an argument to run.
You could also create a shell script that would contain a for loop that you could pass into it 2 arguments. The number of times to run X, and the argument to operate on X.
