I got the below file hierarchy in my Linux system. Wondering what it means to have two dots prefixed to a directory name?
/run/mydir # ls -la
total 4
drwxrwxrwt 3 root root 140 Sep 22 13:03 .
drwxr-xr-x 3 root root 4096 Sep 30 06:26 ..
drwxr-xr-x 2 root root 100 Sep 22 13:03 ..2019_09_22
lrwxrwxrwx 1 root root 31 Sep 22 13:03 ..data -> ..2019_09_22
lrwxrwxrwx 1 root root 13 Sep 22 13:03 address -> ..data/address
lrwxrwxrwx 1 root root 16 Sep 22 13:03 name -> ..data/name
lrwxrwxrwx 1 root root 12 Sep 22 13:03 cell -> ..data/cell
/run/mydir # ls -la ../
total 8
drwxr-xr-x 3 root root 4096 Sep 30 06:26 .
drwxr-xr-x 3 root root 4096 Sep 30 06:26 ..
drwxrwxrwt 3 root root 140 Sep 22 13:03 mydir
/run/mydir #
It has no significance except that ls will not normally list the names because the first character is a dot .. To see names beginning with a dot, you need ls -a or thereabouts, as you show. It looks like a convention that someone with root privileges on your machine likes as a way to identify other directories, but that's about all.
We could guess that over time, there might eventually be other directories such as ..2019_09_29 and that ..data might be rigged to point to the directory currently being analyzed, but that's guesswork.
There are always two default directories:
single period (.) = Current Directory
Double Period (..) = Parent Directory
Related
When I run script as regular user manually, everything is OK. But if an email is received and piped into Go script, I can not open serial port because file does not exist.
postfix 1239 1025 0 13:20 ? 00:00:00 pipe -n watchParadox -t unix flags=F user=watch argv=/usr/local/bin/watch -paradox
watch 1240 1239 0 13:20 ? 00:00:00 /usr/local/bin/watch -paradox
Script is running under watch user who has been added to dialout group, postfix user, just to be sure, is in dialout also.
In my script I ran ls -la command to find out which files do truly exist:
drwxr-xr-x 6 root root 380 Feb 25 13:19 .
dr-xr-xr-x. 18 root root 4096 Feb 22 17:53 ..
lrwxrwxrwx 1 root root 11 Feb 25 13:19 core -> /proc/kcore
lrwxrwxrwx 1 root root 13 Feb 25 13:19 fd -> /proc/self/fd
crw-rw-rw- 1 root root 1, 7 Feb 25 13:19 full
drwxr-xr-x 2 root root 0 Feb 25 13:19 hugepages
lrwxrwxrwx 1 root root 28 Feb 25 13:19 log -> /run/systemd/journal/dev-log
drwxrwxrwt 2 root root 40 Feb 25 13:19 mqueue
crw-rw-rw- 1 root root 1, 3 Feb 25 13:19 null
lrwxrwxrwx 1 root root 8 Feb 25 13:19 ptmx -> pts/ptmx
drwxr-xr-x 2 root root 0 Feb 25 13:19 pts
crw-rw-rw- 1 root root 1, 8 Feb 25 13:19 random
drwxrwxrwt 2 root root 40 Feb 25 13:19 shm
lrwxrwxrwx 1 root root 15 Feb 25 13:19 stderr -> /proc/self/fd/2
lrwxrwxrwx 1 root root 15 Feb 25 13:19 stdin -> /proc/self/fd/0
lrwxrwxrwx 1 root root 15 Feb 25 13:19 stdout -> /proc/self/fd/1
crw-rw-rw- 1 root root 5, 0 Feb 25 13:19 tty
crw-rw-rw- 1 root root 1, 9 Feb 25 13:19 urandom
I am certain following file exists but is not shown when postfix pipe is executed.
crw-rw---- 1 root dialout 166, 0 25. úno 13.19 ttyACM0
I tried chmod 777 on the file but no luck in that department. Opening file via https://github.com/tarm/serial library which uses Go function:
os.OpenFile("ttyACM0", syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_NONBLOCK, 0666)
results with
ttyACM0: no such file or directory
The problem is not the path because I tried relative (using chdir) and absolute with same exact outcome.
I even disabled SELinux which is not what I want to do but in search of solution I try anything.
Code is OK because manual execution of the script passes through properly. I think there is something wrong with Linux settings.
The correct path the ttyACM0 is /dev/ttyACM0. You define a udev rules to set the file mode when it attaches.
If that is not reachable from your program, it might be the case that your program runs chrooted().
It seems like it was truly Linux problem and some underlying fabrics of it which I do not understand. I was running Fedora25 but the problem does not occur on Debian8.
I was able to connect to my school server via SSH. I had an assignment in which I was supposed to use the touch command to create a new file. Yet it keeps returning permission denied. Others were able to do the same thing. Though why do I keep getting this error?
Below is what was the input from the terminal.
Last login: Tue Aug 23 09:16:18 on ttys000
Dominiks-Air:~ fsociety95$ ssh djaneka1#navajo.dtcc.edu
djaneka1#navajo.dtcc.edu's password:
Last login: Tue Aug 23 09:16:35 2016 from pool-72-94-210-193.phlapa.fios.verizon.net
Navajo is Linux shell server provided to staff, faculty, and students. The
operating system is RedHat Enterprise Linux 5.
Alpine, a Pine replacement, has been provided as a mail client. Run "pine"
at the command prompt.
This server also provides web space to users. Web pages can be stored in
the ~/www directory. This is also accessible by mapping a drive in Windows
to \navajo\homepage. The URL for your homepage is
http://user.dtcc.edu/~username/.
Your home directory is also accessible in Windows by mapping to
\navajo\.
If something appears broken or missing, please email path#dtcc.edu.
Could not chdir to home directory /u/d/j/djaneka1: No such file or directory
-bash-3.2$ touch today
touch: cannot touch `today': Permission denied
-bash-3.2$ pwd
/
-bash-3.2$ touch today
touch: cannot touch `today': Permission denied
-bash-3.2$
Edit: here is the result of ls -al
-bash-3.2$ ls -al
total 204
drwxr-xr-x 25 root root 4096 Aug 22 16:50 .
drwxr-xr-x 25 root root 4096 Aug 22 16:50 ..
-rw-r--r-- 1 root root 0 Aug 3 14:01 .autofsck
-rw-r--r-- 1 root root 0 Jan 30 2009 .autorelabel
-rw------- 1 root root 2050 Aug 3 14:00 .bash_history
drwxr-xr-x 2 root root 4096 May 4 04:14 bin
drwxr-xr-x 4 root root 3072 Aug 3 13:57 boot
drwxr-xr-x 11 root root 4060 Aug 3 14:02 dev
drwxr-xr-x 87 root root 12288 Aug 23 10:05 etc
drwxr-xr-x 3 root root 4096 Oct 1 2009 home
drwxr-xr-x 13 root root 12288 Jun 1 04:09 lib
drwx------ 2 root root 16384 Mar 24 2008 lost+found
drwxr-xr-x 3 root root 4096 Oct 1 2009 media
drwxr-xr-x 2 root root 0 Aug 3 14:02 misc
drwxr-xr-x 4 root root 4096 May 26 2012 mnt
drwxr-xr-x 2 root root 0 Aug 3 14:02 net
drwxr-xr-x 9 root root 4096 Jan 5 2009 nsr
drwxrwxr-x 3 root root 4096 Oct 12 2015 opt
dr-xr-xr-x 219 root root 0 Aug 3 14:01 proc
drwxr-x--- 12 root root 4096 Apr 22 10:06 root
drwxr-xr-x 2 root root 12288 Aug 4 04:02 sbin
drwxr-xr-x 2 root root 4096 Oct 1 2009 selinux
drwxr-xr-x 2 root root 4096 Oct 1 2009 srv
drwxr-xr-x 11 root root 0 Aug 3 14:01 sys
drwxrwxrwt 38 root root 4096 Aug 23 10:07 tmp
drwxr-xr-x 34 root root 4096 Jun 21 08:29 u
drwxr-xr-x 14 root root 4096 Apr 16 2010 usr
drwxr-xr-x 24 root root 4096 Apr 16 2010 var
-rw------- 1 root root 2865 Dec 16 2008 .viminfo
-bash-3.2$
EDIT:
Here is what I see after trying touch today in /home
So to try and create a new document in the root directory you need to be recognised as root. That means using the sudo command.
However for that you would need a password that you may not have. If you do perfect. But in any case I would not recommend adding files to the root directory.
Instead try the following:
cd home
touch today
This should work just fine and answer your question.
Still if you need/want to create today in your root directory try the following
sudo touch today
You will then be prompted for the root password that you can type (if you have it obviously)
In any case I suggest reading this which may be very helpful for you.
I wonder if this was ever truly answered.
If I was looking at it, I would try to see what the system thinks is the home directory of djaneka1, since it may have been setup partway and not completed, leaving stuff owned by root that should have been owned by djaneka1.
If you use the pwd command, and get back the "/" (root) directory there is something wrong with your setup.
The message: Could not chdir to home directory /u/d/j/djaneka1: No such file or directory
tells you it can't find your home directory.
-bash-3.2$ pwd
/
the command "pwd" revealing "/" is just an artifact of the system not being able to find your home directory.
To find what the system thinks is one's home directory,
one can search the file named '/etc/passwd' for one's login name.
I expect this is a possible result if you do that:
$ fgrep 'djaneka1' /etc/passwd
djaneka1:x:1505:1506::/u/d/j/djaneka1:/bin/bash
since it complained that it couldn't find that directory.
This needs to be fixed by someone who has more rights to the system, like root.
there is nothing djaneka1 can do a
I accidentally created some folders with special characters. I already read the other posts in stackoverflow, but don't work. When I type the ls -la command I see
root#mycomputer:/myfolder# ls -la
drwxr-xr-x 3 root root 4096 feb 6 17:53 ,
drwxr-xr-x 70 root root 4096 feb 11 10:27 .
drwxr-xr-x 6 root root 4096 feb 11 09:16 ..
drwxr-xr-x 7 root root 4096 feb 9 22:45 (
drwxr-xr-x 3 root root 4096 feb 2 22:01 [
drwxr-xr-x 3 root root 4096 feb 6 08:11 $
drwxr-xr-x 3 root root 4096 feb 2 23:15 \
drwxr-xr-x 4 root root 4096 feb 8 10:34 &
drwxr-xr-x 5 root root 4096 feb 8 09:43 #
drwxr-xr-x 3 root root 4096 feb 6 14:41 +
drwxr-xr-x 6 root root 4096 feb 6 09:15 ?
drwxr-xr-x 4 root root 4096 feb 6 04:07 ?
drwxr-xr-x 5 root root 4096 feb 6 01:13 ?
drwxr-xr-x 3 root root 4096 feb 6 02:25 ?
drwxr-xr-x 5 root root 4096 feb 3 12:25 ?
drwxr-xr-x 4 root root 4096 feb 5 23:18 ?
I can't do anything with the ones pointed as question marks
I tried to type the command mv and then press tab and this is what I get
root#mycomputer:/myfolder# mv
,/ ▒/ 7/ h/
(/ ▒/ 8/ i/
[/ ▒/ 9/ j/
$/ ▒/
\/ ▒/
So apparently I can't rename them in order to delete them.
Any ideas?
What finally worked for me was one of the answers I found in this question:
rm all files except some
rm !(textfile.txt|backup.tar.gz|script.php|database.sql|info.txt)
If you don't need the other directories, you can just
rmdir ?
Or, use character class (supported e.g. in bash):
rmdir [^789hij] # removes all one-character directories except for 7, 9, etc.
You can also try mc or some other file manager.
please explain me why on x86_64 Scientific Linux no file under /etc/ld.so.conf.d contains the directory /usr/lib64?
The list of directories to be searched by program loader is stored in the file /etc/ld.so.conf. On my distributive, this file stores this row: include ld.so.conf.d/.conf*
And the above directory consists of:
[root#dev_host build]$ ls -la /etc/ld.so.conf.d
total 36
drwxr-xr-x. 2 root root 4096 Aug 29 23:13 .
drwxr-xr-x. 103 root root 12288 Sep 18 03:41 ..
-rw-r--r--. 1 root root 17 Mar 20 2012 atlas-x86_64.conf
-r--r--r--. 1 root root 324 May 7 23:40 kernel-2.6.32-431.17.1.el6.x86_64.conf
-r--r--r--. 1 root root 324 Nov 22 2013 kernel-2.6.32-431.el6.x86_64.conf
-rw-r--r--. 1 root root 17 Feb 12 2014 mysql-x86_64.conf
lrwxrwxrwx 1 root root 31 Aug 11 14:46 postgresql-pgdg-libs.conf -> /etc/alternatives/pgsql-ld-conf
-rw-r--r--. 1 root root 22 Sep 7 2011 qt-x86_64.conf
I examined all these files - there is no /usr/lib64. Why? Is it stored in /etc/ld.so.cache?
I need to write rotation of files shell script. I have following format data in a target directory(/backup/store_id/dates_folders)
Like :
cd /backup/
drwxr-xr-x 5 root root 4096 Mar 25 12:30 44
drwxr-xr-x 3 root root 4096 Mar 25 12:30 45
drwxr-xr-x 4 root root 4096 Mar 25 12:30 48
drwxr-xr-x 3 root root 4096 Mar 25 12:30 49
cd /backup/44/
drwxr-xr-x 2 root root 4096 Mar 25 12:30 22032014
drwxr-xr-x 2 root root 4096 Mar 25 12:30 23032014
drwxr-xr-x 2 root root 4096 Mar 25 12:30 24032014
drwxr-xr-x 2 root root 4096 Mar 25 12:30 25032014
now 44 (store_id) contain four dates folders. I want each store_id( like 44 folder) contain only three recent dates folder like 23,24,25 & 22 should be deleted. Please help me how to write in shell script. Please give me some hint
This should work:
cd /backup && ls -d */ | while read storeId; do rm -r `ls -r $storeId | tail -3`; done
I assume here that directory names are more important than their timestamps...
If that is not the case, you should use ls -tr instead of ls -r, to let ls command sort on timestamps...