I didn’t realize that. Thanks for pointing that out!
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It would not, as @Quibblekrust@thelemmy.club explained in their comment (which I neglected to include in my explanation), Bash uses a special variable called
IFSwhen executing for loops like this.IFSstands for Input Field Separators, and is a list of one of each type of whitespace (tab, space, and newline), and uses these as separators automatically.So instead of taking that whole
lsoutput as one string of text, the for loop automatically separates it into an iterable list of strings using the newline separator.
I was also a teach for a number of years! Hello fellow teacher. :)
I agree. Bash, and GNU/Linux in general is amazing. My recent foray has been into Python, and I’m having an utter blast writing code and learning.
You’ve got a few things going on to be broken down here.
And forgive me if anything I say here seems condescending, it’s not meant to be, I just like to be very explanatory with things like this and to assume the reader may not know anything about anything. (Not as an insult, but simply as a gap in knowledge).
Also, while I’m proficient at Bash, I’m no expert.
LIST=$(ls): Here you’ve stored the output of thelscommand to the variable LIST, which gives you a list of items in the given directory, in this case, whichever directory the command is run from. It’s also a good idea to quote the variable assignment like this:"$(ls)".for i in $LIST;: This is the first part of the for loop statement, which is an iterator, meaning, it will loop or iterate over every item in the given variable/parameter/group of iterable items.The
ihere, as you said could be anything. You could sayfor file in $LIST;orfor item in $LIST;. It doesn’t matter, because it’s just a variable name that you are using in the first part of the for statement.So what bash will do with this is loop over the list, and take each item in the list, and assign it to the variable
i, which will allow you do act upon that single item by calling the variableiin some other commands.do echo "I found one!";: This is the next part of the for loop, which is the instruction set to be executed inside the for loop. Here is where you can act upon the items in your list that have been assigned to the variablei.In your case, you’re just printing a statement to
stdout(standard out), that says, “I found one!”It’s like saying, for each item in this list, print “I found one!”
So if there are 20 items in the list, it will print that statement 20 times.
However, maybe you want to print the item itself as part of a statement. So instead of “I found one!”, you could do something like:
do echo "I found $i!"Which then would print “I found some-filename-or-directory-here!” for each item in your list.
done: Finally, thedonestatement tells bash that this is the end of the for loop. So any commands after thedonestatement will only run once the for loop has iterated over all items in the list and executed the commands inside the for loop for each item on the list.A couple of notes:
The
;is used as a command separator or terminator. So bash knows to first runLIST=$(ls)before it attempts to run whatever the next command might be.In bash, it’s good practice to always quote your variables like so:
for i in "$LIST";. This is to avoid errors for characters that might need escaping like whitespace, backslashes, and other special characters.With that in mind, if you’re running a command like
echo "I found $i!", you don’t need to quote the variable again, because it’s already inside a quote set.Further, it’s not absolutely necessary, but it can also be a good idea to also enclose all of your variables in
{}, so whenever you use a variable, you’d do something like:"${LIST}"This not only more clearly identifies variables in your bash scripts/commands, but is necessary when using bash’s parameter expansion, which is pretty great.
harsh3466@lemmy.mlto
Linux@lemmy.ml•What are some of your most useful or favorite terminal commands?
9·1 month agofind /path/to/starting/dir -type f -regextype egrep -regex 'some[[:space:]]*regex[[:space:]]*(goes|here)' -exec mv {} /path/to/new/directory/ \;I routinely have to find a bunch of files that match a particular pattern and then do something with those files, and as a result,
findwith-execis one of my top commands.If you’re someone who doesn’t know wtf that above command does, here’s a breakdown piece by piece:
find- cli tool to find files based on lots of different parameters/path/to/starting/dir- the directory at which find will start looking for files recursively moving down the file tree-type f- specifies I only wantfindto find files.-regextype egrep- In this example I’m using regex to pattern match filenames, and this tellsfindwhat flavor of regex to use-regex 'regex.here'- The regex to be used to pattern match against the filenames-exec-execis a way to redirect output in bash and use that output as a parameter in the subsequent command.mv {} /path/to/new/directory/-mvis just an example, you can use almost any command here. The important bit is{}, which is the placeholder for the parameter coming fromfind, in this case, a full file path. So this would read when expanded,mv /full/path/of/file/that/matches/the/regex.file /path/to/new/directory/\;- This terminates the command. The semi-colon is the actual termination, but it must be escaped so that the current shell doesn’t see it and try to use it as a command separator.
harsh3466@lemmy.mlto
Selfhosted@lemmy.world•What DDNS providers you guys recommend?English
2·1 month agoI used duckdns for years without any issues at all. Only reason I switched is because I’m using Pangolin and tunneling instead of exposing my IP directly.
Sorry, typo. It’s Play:sub
Unfortunately, yes
Android or iOS?
On android I found symphonium to be a great app to use with my navidrome server. On iOS, play:sub was the best experience I found
harsh3466@lemmy.mlto
Selfhosted@lemmy.world•The 'if this goes down, I riot' self-hosted appEnglish
51·2 months agodeleted by creator
harsh3466@lemmy.mlto
Selfhosted@lemmy.world•jotty·page - Checklists & Notes made it easyEnglish
5·3 months agoThis looks awesome. I’m going to check it out.
I should have added a /s.
Canonical controls the back end and that (along with how canonical has treated snaps in Ubuntu pulling them in with apt calls) are two major reasons snaps get (justified) hate
The huge benefit (to canonical) is that they control the store/repo.
harsh3466@lemmy.mlto
Linux@lemmy.ml•I just found out my fiancee wants to switch to linux, lets start a distro war, what should be her first? + other questions
4·3 months agoCome on gang! We all know the real answer is Hannah Montana!
harsh3466@lemmy.mlto
Open Source@lemmy.ml•Introducing Ultimate Audiobooks, the one stop shop for file cleaning
5·4 months agoFWIW, they don’t have an api. It’s on their long term roadmap.
To check for an empty string, use
-z.-nchecks to see if a string is not empty.
harsh3466@lemmy.mlto
Selfhosted@lemmy.world•Forgejo fills up hard drive with repo-archivesEnglish
2·4 months agoI don’t know the specifics but forgejo is a gitea fork. There was/is some controversy around gitea governance and movent towards prioritizing a closed source paid/private versions of gitea.
Again, I don’t know details, just very broad strokes. I chose forgejo because it’s under active Foss development and I didnt want to deal with potentially going with gitea and then having to abandon it later for whatever reason might develop.
harsh3466@lemmy.mlto
Selfhosted@lemmy.world•Forgejo fills up hard drive with repo-archivesEnglish
12·4 months agoAnd I totally understand that. These AI crawlers really suck.


Excuse me, it’s microslop. ;)