xargs: initial notes

src/SUMMARY.md

@@ -17,6 +17,7 @@
     - [tac](./cli/tac.md)
     - [rev](./cli/rev.md)
     - [paste](./cli/paste.md)
+    - [xargs](./cli/xargs.md)
 
 - [Tools](./tools/README.md)
     - [tmux](./tools/tmux.md)

src/cli/README.md

@@ -9,3 +9,4 @@
 - [tac](./tac.md)
 - [rev](./rev.md)
 - [paste](./paste.md)
+- [xargs](./xargs.md)

src/cli/xargs.md

@@ -0,0 +1,23 @@
+# xargs(1)
+
+```
+xargs [opts] [cmd [init-args]]
+    -l [<num>]   maximal number of lines per cmd invocation
+                 if <num> it not provided, num=1 is assumed
+    -I <str>     replace <str> in the [init-args] with the arg;
+                 this implies -l, and hence processes one arg at a time
+```
+
+## Example
+
+Collect arguments and prefix them with another option.
+```sh
+# Using -l to process one arg at a time.
+eval strace -f (find /dev -name 'std*' | xargs -l echo -P | xargs) ls
+
+# Using -I to place the arg at the specified location.
+eval strace -f (find /dev -name 'std*' | xargs -I {} echo -P {}) ls
+
+# Both commands achieve the same thing and result in something like:
+#   eval strace -f -P /dev/stdin -P /dev/stdout -P /dev/stderr ls
+```