31–40 of 135 posts
awk '{ print your_command }' | bash Never can remember all the -I stuff around xargs
I wouldn't say "never use it", but I would hesitate to ever put it in a script, vs. doing a one-off at the command line.
rm $(ls | grep foo)
will not work if you have file names that contain spaces.
Shell programming is planted thick with landmines like this.
Wanting verbose logging from xargs, years ago I wrote a script called `el` (edit lines) that basically does `xargs -0` with logging. https://github.com/westurner/dotfiles/blob/develop/scripts/e... It turns out that e.g. -print0 and -0 are the only safe way: line endings aren't escaped: find . -type f -print0 | el -0 --each -x echo GNU Parallel is a much better tool: https://en.wikipedia.org/wiki/GNU_parallel
(author here) Hm I don't see either of these points because: GNU xargs has --verbose which logs every command. Does that not do what you want? (Maybe I should mention its existence in the post) xargs -P can do everything GNU parallel do, which I mention in the post. Any counterexamples? GNU parallel is a very ugly DSL IMO, and I don't see what it adds. -- edit: Logging can also be done with by recursively invoking sh…
I frequently find myself reaching for this pattern instead of xargs: do_something | ( while read -r v; do . . . done ) I’ve found that it has fewer edge cases (except it creates a subshell, which can be avoided in some shells by using braces instead of parens)
I frequently find myself reaching for this pattern instead of xargs: do_something | ( while read -r v; do . . . done ) I’ve found that it has fewer edge cases (except it creates a subshell, which can be avoided in some shells by using braces instead of parens)
Wanting verbose logging from xargs, years ago I wrote a script called `el` (edit lines) that basically does `xargs -0` with logging. https://github.com/westurner/dotfiles/blob/develop/scripts/e... It turns out that e.g. -print0 and -0 are the only safe way: line endings aren't escaped: find . -type f -print0 | el -0 --each -x echo GNU Parallel is a much better tool: https://en.wikipedia.org/wiki/GNU_parallel
> That is, grep doesn't support an analogous -0 flag.
However, the GNU grep variant does have an analogous flag:
-z, --null-data
Treat the input as a set of lines, each terminated by a zero byte (the ASCII NUL character) instead of a newline. Like the -Z or --null option, this option can be used with commands like sort -z to process arbitrary file names.
I frequently find myself reaching for this pattern instead of xargs: do_something | ( while read -r v; do . . . done ) I’ve found that it has fewer edge cases (except it creates a subshell, which can be avoided in some shells by using braces instead of parens)
For thousands of arguments this sloution is much slower (high CPU usage) than xargs, because either it implements the logic as a shell script (slow) or it runs an external program for each argument (slow).
Wanting verbose logging from xargs, years ago I wrote a script called `el` (edit lines) that basically does `xargs -0` with logging. https://github.com/westurner/dotfiles/blob/develop/scripts/e... It turns out that e.g. -print0 and -0 are the only safe way: line endings aren't escaped: find . -type f -print0 | el -0 --each -x echo GNU Parallel is a much better tool: https://en.wikipedia.org/wiki/GNU_parallel
Yeah but xargs doesn't refuse to run until I have agreed to a EULA stating I will cite it in my next academic paper.
Parallel is the better tool but the nagware impairs its reputation.