I wanted to delete some package in my home file, but the filename was too long (google-chrome-stable_current_i386.deb
). So, I decided to use the command ls|grep chrome|rm
to pipe the files to grep to filter out the chrome file, and then remove it. It didn't work, so I would like to see how I can do this.
6 Answers
This almost made me wince.
- You might want to stop pointing that shotgun at your foot. Basically any kind of parsing of
ls
is going to be more complicated and error-prone than established methods likefind [...] -exec
or globs. - Unless someone installed a troll distro for you, your shell has Tab completion. Just type
rm google
and press Tab. If it doesn't complete immediately, press Tab again to see a list of matching files. Type more characters of the filename to narrow it down until it does complete, then run the command. - Pipes != parameters. Standard input is a binary data stream which can be fed to a command asynchronously. Parameters are space separated strings which are passed once and only once to a command when running it. These are very rarely interchangeable.
-
4Sorry if it seemed like a n00b question. I knew it was okay to use generally, as the package stated was the only package with "chrome" stated in it. Therefore, using grep would filter out only one file. I am pretty new to linux, and I have already done plenty of bash scripts, but I don't know everything yet :P. Harsh, dude. Dec 7, 2015 at 20:45
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7Didn't mean to be harsh, but the shell is a harsh and unforgiving environment, hidden behind a kinda user friendly surface. Doing things safely is difficult enough, never mind securely or even correctly.– l0b0Dec 7, 2015 at 22:12
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4@SpecialBomb This is the only correct answer. Explaining how to correctly aim said shotgun to cleanly cut off one's foot, as the other answers do, is certainly not the way to go. Be especially careful of blindly executing
rm
- it's probably the single more common way to fry your distro. Dec 8, 2015 at 9:58 -
1@stevec If you want clarity around how
find
works I would recommendman find
or asking another question here. "anything else to be aware of" is a theme big enough for a book.– l0b0May 9, 2020 at 20:09 -
1It bugs me that this is the accepted answer, but it isn't the answer. It's advice for a path to the answer... and all that was needed as icing on the cake was the actual way to use find properly. Voting up the other answer that provided that instead. Jul 20, 2021 at 1:57
You had the right idea, just missed some details. Since you're dealing with a list coming to STDIN and rm
expects parameters, you need to use xargs
.
Thus:
ls | grep chrome | xargs rm
Should give you what you want.
Note that if you want to delete everything other than the chrome
file, you can simply add -v
to the grep
statement.
Note that, per the other answers to this question, this is probably a bad way of accomplishing what you want to accomplish.
-
With
-v
, wouldn't this delete everything except for files that matchchrome
? I don't think that's what the OP wants... Dec 7, 2015 at 18:24 -
Looking again, you're correct. The OP wants to "filter out the chrome file", but then wants to remove it.– JohnDec 7, 2015 at 18:44
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5The accepted answer works, but see the answer below which explains why it's a bad idea. (Posting this comment here only for the sake of those who stop as soon as they see an "accepted" checkmark.) Dec 8, 2015 at 17:24
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2This, the accepted answer "works" only if there are no "weird" filenames in the
ls
output. Filenames with spaces will wreck this. This is also dangerous if someone can construct a filename with special sauce in the directory where you run this. As more than one person has already pointed out, don't parse the output of ls! Dec 9, 2015 at 2:15
You can also use the find command with a wildcard:
find . -maxdepth 1 -name '*chrome*' -delete
Note that the "-maxdepth" argument ensures that find only works in the current directory, and doesn't recurse into subdirectories.
-
1Suggestions for improvements: (a) use
-iname
for case-insensitive filenames (b) pipe toxargs
using-print0
flag forfind
and-0
flag forxargs
. The use ofxargs
allows you to do things like "interactive" (confirm deletefoo
?) deletes. Dec 7, 2015 at 22:15 -
3No need to pipe to xargs if you use -exec option:
find . -name '*chrome*' -exec rm -i {} +
– JohnnyDec 7, 2015 at 23:53 -
4Won't this also delete recursively into subdirectories? You may need to specify
maxdepth
to be 1.– TyzoidDec 8, 2015 at 12:48
Never parse the output of ls
My suggestion is to avoid to parse the output of ls [1], even more if in conjunction with the del
command. This for many reasons mainly related to unexpected and not usual characters allowed in the file name.
Even when you should expect that the filenames belonging to Linux packages will "behave well", this problem can nonetheless appears if other files are present in the same directory but you didn't know or notice.
It's better to use find
, the tab expansion (start to write the name and press Tab), the file name expansion [2] as *MyKey*
...
A fast solution
Since you want to select all the packages (that finish with .deb
) with "google" inside you can build your request with the wildcard *
*google*.deb
and do a simple
rm -i *google*.deb
that will select each filename with "google" in the middle that will finish for .deb
present in the current directory. The option -i
(interactive) will prompt for the confirmation, a good habit when you delete files with the parameter expansion.
A solution close to the philosophy of your attempt
If your purpose is to build your commandline piece after piece, so you have done ls
, after ls | grep google
, and only after you checked your output you can execute it in a subshell $(...)
with
rm -i $(ls | grep google)
A faster and more dangerous way [3], is to use !!
ls | grep google
rm -i $(!!)
that will execute the last command finished in your history. You can protect yourself from the fact that you have no visual control of the line that you are going to execute if you have enabled in advance the shell options histverify
with shopt -s histverify
.
touch 0 1 2 3 4 5 6 7 8 9
find . -name \[0-9] -ok rm {} \;
< rm ... ./0 > ? y
< rm ... ./9 > ? y
< rm ... ./8 > ? y
< rm ... ./7 > ? y
< rm ... ./6 > ? y
< rm ... ./5 > ? y
< rm ... ./4 > ? y
< rm ... ./3 > ? y
< rm ... ./2 > ? y
< rm ... ./1 > ? y
^C
...use -name '*c*.deb'
or some other pattern as suits you instead.
rm
doesn't accept input from stdin
. You'll need to do something like ls google-chrome* | xargs rm
rm -i *chrome*.deb
ls
find
-find . -name "*chrome*" -delete
.ls
throughgrep
torm
but couldn't get it to work. That way you'll get one or two good answers about the "correct" or "easiest" way to accomplish your task rather than forcing someone to give you a good answer about an inefficient solution.