I have this file in my mounted partition
/path/to/hardDiskDrive/$ ls -l
-rw------- 1 arash arash 92827804 Jun 15 17:35 qt-creator-opensource-linux-x86_64-4.0.2.run
and then try to chmod it but nothing happens even with sudo
/path/to/hardDiskDrive/$ chmod +x qt-creator-opensource-linux-x86_64-4.0.2.run
/path/to/hardDiskDrive/$ ls -l
-rw------- 1 arash arash 92827804 Jun 15 17:35 qt-creator-opensource-linux-x86_64-4.0.2.run
but when i copy it to my Linux home directory everything works fine ..
What is the resne of this ?!!
~/Desktop $ ls -l
-rw------- 1 arash arash 92827804 Jun 15 17:35 qt-creator-opensource-linux-x86_64-4.0.2.run
~/Desktop $ chmod +x qt-creator-opensource-linux-x86_64-4.0.2.run
~/Desktop $ ls -l
-rwx--x--x 1 arash arash 92827804 Jun 15 17:35 qt-creator-opensource-linux-x86
What is the reason of this?!! and How can i run this file from original place in Hard Drive?
thanks
Related
I have a question about setuid:
for example, there is a file - 1.txt, only root has write permission:
$ll 1.txt
-rw-r--r--. 1 root root 57 Jul 1 12:19 1.txt
For an ordinary user to modify the file, I did the following:
$ sudo chmod u+s /usr/bin/echo
$ ll /usr/bin/echo
-rwsr-xr-x. 1 root root 33128 Oct 31 2018 /usr/bin/echo
However, when the user ran below command, it still got permission error.
$ echo 111 > 1.txt
bash: 1.txt: Permission denied
Then I did a similar test on ls command：
Only root has write permission to test/ directory:
$ ll -d test/
drw-------. 2 root root 34 Jul 1 14:18 test/
a user that run ls command would report an error
$ ls test/
ls: cannot open directory test/: Permission denied
Then setuid on ls command:
$ sudo chmod u+s /usr/bin/ls
$ ll /usr/bin/ls
-rwsr-xr-x. 1 root root 117680 Oct 31 2018 /usr/bin/ls
after this, the user was able to run the command
$ ls test/
1 23 4
What's the difference between echo and ls? Or what I missed here?
I used the 'find' command to find a file and encountered a strange issue:
the file exists, but 'find' can't find it
I found two .sock in /run with 'sudo find /run -name docker.sock'
$sudo find /run -name docker.sock
/run/march/docker.sock
/run/docker.sock
I got nothing when run 'sudo find /var -name docker.sock' and 'sudo find /var/run -name docker.sock'
$sudo find /var -name docker.sock
$sudo find /var/run -name docker.sock
$
but in fact there are two .sock in /var/run/, any comments?
$ls -al /var/run/docker.sock
srwxrwxrwx+ 1 root docker 0 Oct 18 20:45 /var/run/docker.sock
$ls -al /var/run/march/docker.sock/
total 0
drwxr-xr-x 2 root root 40 Oct 31 20:35 .
drwxr-xr-x 5 root root 100 Oct 31 20:35 ..
$ls -al /var/run/march/
total 0
drwxr-xr-x 5 root root 100 Oct 31 20:35 .
drwxr-xr-x 34 root root 1120 Oct 31 23:45 ..
drwxr-xr-x 2 root root 40 Oct 31 20:35 docker
drwxr-xr-x 2 root root 40 Oct 31 20:35 docker.pid
drwxr-xr-x 2 root root 40 Oct 31 20:35 docker.sock
$
$
BTW it's on Ubuntu 20.04.2 LTS
Thanks in advance
As /var/run is a symbolic link to /run, you have to tell find to follow links :
sudo find -L /var/run -name docker.sock
The program I'm running inside the Docker image, first creates a directory and writes some file into the directory.
To transfer the directory onto the host machine, I've mounted a datadir/ and then moved the directory created inside the image into the mounted directory, e.g.:
mkdir datadir
DATADIR=datadir/
docker run -i \
-v $(pwd)/$DATADIR:/$DATADIR/ ubuntu \
bash -c "mkdir /x1 && echo 'abc' > x1/test.txt && mv x1 $DATADIR"
But when I tried to access datadir/x1, it has root as the owner and it comes with read-only permissions:
$ mv datadir/x1/ .
mv: cannot move 'datadir/x1/' to './x1': Permission denied
$ ls -lah datadir/x1/
total 12K
drwxr-xr-x 2 root root 4.0K Jun 28 16:38 .
drwxrwxr-x 3 alvas alvas 4.0K Jun 28 16:38 ..
-rw-r--r-- 1 root root 4 Jun 28 16:38 test.txt
Is mounting the additional volume and copying the created directory inside the image the right approach to move files between the Docker image and the host machine? If not, what's the "canonical" way to perform the same operation?
About the directory permissions, what should be the correct way to assign the host machine permission to any files inside the mounted volume?
I've tried to chmod -R 777 inside the Docker image but I don't think that's the safe approach, i.e.:
$ docker run -i -v $(pwd)/$DATADIR:/$DATADIR/ -i ubuntu bash -c "mkdir /x1 && echo 'abc' > x1/test.txt && mv x1 $DATADIR && chmod -R 777 $DATADIR"
$ mv datadir/x1/ .
$ ls -lah x1
total 12K
drwxrwxrwx 2 root root 4.0K Jun 28 16:47 .
drwxrwxr-x 12 alvas alvas 4.0K Jun 28 16:47 ..
-rwxrwxrwx 1 root root 4 Jun 28 16:47 test.txt
To avoid permission issues use docker cp
For example:
# This is the directory you want to save the outputs
mkdir datadir
# We create a directory and file inside it, inside the Docker image.
# And we are naming the Docker image "thisinstance"
docker run -i --name thisinstance ubuntu \
bash -c "mkdir /x1 && echo 'abc' > x1/test.txt"
# Copies the new directory inside the Docker image to the host.
docker cp thisinstance:/x1 datadir/
# Destroy the temporary container
docker rm thisinstance
# Check the ownership of the directory and file
ls -lah datadir/x1/
[out]:
drwxr-xr-x 3 alvas 679754705 102B Jun 29 10:36 ./
drwxr-xr-x 3 alvas 679754705 102B Jun 29 10:36 ../
-rw-r--r-- 1 alvas 679754705 4B Jun 29 10:36 test.t
I am trying to set SGID bit on all directories within this directory, but uanble to do so.
Can anybody please help ?
$ ls -ld Music
drwxrwxr-x 16 pankaj usrgrp 1024 Apr 14 14:54 Music
$ chmod -R g+s Music
$ echo $?
0
$ ls -ld Music
drwxrwxr-x 16 pankaj usrgrp 1024 Apr 14 14:54 Music
$
I have a symlink for my live server called current and I have releases in the releases directory, i.e current -> releases/2012-05-08_15-13
If I want to update the symlink of my current directory, I have to unlink/rm it and re ln -s it.
My question is: How can I remove the symlink and update it to the latest release in one step.
The form of ln is
ln -sf sourcefile targetlink
Try
ln -sf releases/2012-05-08_15-13 current
to remove the current and create the new link.
If you want to do it in a single command, do as #hughw suggests and run ln -sf.
If you want to replace the symlink atomically (ie. so that there's no point in time where the symlink doesn't exist) create a new symlink, then mv it over the old one.
As suggested by ToddR, here is the only answer that actually works on maybe most flavours of Linux - definately Ubuntu - which uses ln from coreutils package). Let me prove it to you.
matthewh#xen:~$ mkdir -p releases/dirA
matthewh#xen:~$ mkdir -p releases/dirB
matthewh#xen:~$ ln -s releases/dirA
matthewh#xen:~$ ls -l dirA
lrwxrwxrwx 1 matthewh matthewh 13 Apr 7 09:58 dirA -> releases/dirA
matthewh#xen:~$ ln -sf releases/dirB
matthewh#xen:~$ rm dirA
matthewh#xen:~$ ln -s releases/dirA current
matthewh#xen:~$ ln -sf releases/dirB current
matthewh#xen:~$ ls -l current
lrwxrwxrwx 1 matthewh matthewh 13 Apr 7 09:59 current -> releases/dirA <--- DOESN'T WORK!
matthewh#xen:~$ ln -sfn releases/dirB current <--- WORKS!
matthewh#xen:~$ ls -l current
lrwxrwxrwx 1 matthewh matthewh 13 Apr 7 09:59 current -> releases/dirB
So the correct method on Linux is:
ln -sfn source target
-n, --no-dereference
treat LINK_NAME as a normal file if it is a symbolic link to a directory
This is essential, if you do not use -n switch you will end up with a symlink inside source directory named "target".
In my examples,
matthewh#xen:~$ ls -l releases/dirA/
total 0
lrwxrwxrwx 1 matthewh matthewh 13 Apr 7 10:03 dirB -> releases/dirB
correct answer:
ln -s new current_tmp && mv -Tf current_tmp current
Move is atomic operation.
Don't use 'ln -snf'.
strace 'ln -snf' shows two system calls unlink + symlink.
This example clears the use of -sfn switch:
drwxr-xr-x. 10 root root 4096 Aug 25 18:24 .
dr-xr-xr-x. 25 root root 4096 Aug 19 10:32 ..
lrwxrwxrwx. 1 wildfly wildfly 25 Aug 25 18:15 wildfly -> /opt/wildfly-8.2.0.Final/
drwxr-xr-x. 10 wildfly wildfly 4096 Aug 25 18:28 wildfly-8.2.0.Final
link to link
| |
[gecloud#ip-10-227-224-45 opt]$ sudo ln -sfn wildfly-8.2.0.Final /opt/wildfly
[gecloud#ip-10-227-224-45 opt]$ ls -la
total 115540
drwxr-xr-x. 10 root root 4096 Aug 25 18:34 .
dr-xr-xr-x. 25 root root 4096 Aug 19 10:32 ..
lrwxrwxrwx. 1 root root 19 Aug 25 18:34 wildfly -> wildfly-8.2.0.Final
drwxr-xr-x. 10 wildfly wildfly 4096 Aug 25 18:28 wildfly-8.2.0.Final