Mv -v "File 002" "I was 2 and now I am File 002" Mv -v "File 001" "I was 1 and now I am File 001" Xargs, which works per word separated by whitespace, sed works exclusivelyĪnd explicitly per line, which is exactly the sort of input I expect from ls. Instead, myįavourite trick is to use sed to craft exactly the commands I want. I could probably do some dark magic involving find -print0 | xargs -0, but even that would struggle with the | bash -c. Introducing spaces into the mix caused xargs to treat "File" and "001" as two Mv: cannot stat '002': No such file or directory Mv: cannot stat '001': No such file or directory Mv: cannot stat 'File': No such file or directory Instead I see: $ ls | xargs -verbose -n 1 bash -c 'mv "$0" "File $0"' In theory I should get "File File 001", but Introduced some in my previous example, so let's see what happens if I runĮxactly the same command again. There's another case that will break xargs: whitespace in filenames. That I'm really not using this tool in the way it was intended to be used. If you compare it to the much simpler syntax of seq 1 100 | xargs touchĮxpression I used to create the files in the first place, it becomes evident Groaning under the load of a use case that's simpler than my rename exampleĪbove. Now, this syntax already has quite a few pieces to remember/get wrong, and it's ![]() $ ls | xargs -verbose -n 1 bash -c 'mv "$0" "File $0"' Onto the end of a single command until it runs out of room. Otherwise, xargs will happily keep glomming arguments I also need to tell xargs to run this command once for each input word, which (It's worth noting that in a shell script, $0 is normally the invocation of My command just like I would if I were writing a very small shell script, ie.Īccepting one (or more!) parameters via the magic variables $0, $1, etc. Workaround I use is to invoke bash -c as a subprocess. I spoke of persuasion to convince xargs to construct valid mv syntax. You to move a file that Git is tracking without breaking its version history.įurthermore, xargs works if your input is a list of files, like from git diff -name-only, and it can be chained with other commands like grep. A good example of this is git mv, which allows It does have the advantage over rename that it can run commands that are You can do that with xargs, but it needs a Of mv, and I need to provide a variation on the filename twice to eachĬommand, as in mv 123 123.bak. I can only rename one file per invocation My friend Julia has a great zine/comic covering more uses of Parameters as I want to throw at it (subject to length requirements that xargsĪlso respects). Known, not crazy (no spaces), and using a command that could take as many Setting up this environment is a classic case for xargs, where my inputs were Pretty well count on xargs to be there when you need it. To 074, which is what I wanted all along.) xargsĪs mentioned, rename doesn't come installed on every machine, but you can ![]() So 74 gets renamed to 0074 and then truncated Semicolon: one to prepend two zeroes to every filename, the second to strip allīut the last three characters. (Here I use a hack involving two regular expressions chained together with a That you'll find preinstalled on some but not all *nix machines, and naturallyįirst off, I forgot to add leading zeroes to those files I created before, so The smoothest experience for simple tasks is rename. (I'll talk about that little piece of magic shortly.) rename ![]() Tool, but learning a few tricks off the top of your head can tip the balance inįavour of automation and save a lot of time.įirst, for demonstration purposes, I'll make a whole lot of files. Now, there's always a tradeoff of number of files vs.Ĭomplexity where the balance of time spent makes sense to reach for an automated Every now and then, I find myself facing a giant pile of files that need
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