Useful bash commands
Search for files (for example
filename.ext) from the root directory:
sudo find / -name filename.ext
Remove directory and its content, without prompts:
sudo rm –rf DIR_NAME
Recursively change the group of a file or folder:
sudo chgrp -R GROUP_NAME PATH/TO/FILE/FOLDER
Recursively change the owner of a file or folder:
sudo chown -R USER_NAME DIRECTORY/FILENAME
Recursively change the owner and the group of a file or folder:
sudo chown -R USER_NAME:GROUP_NAME DIRECTORY/FILENAME
Lists the content of the working directory in long format:
...Results of the above command you look something like the following:
total 72 -rw-r--r-- 1 root root 9677 Apr 10 01:53 apache2.conf drwxr-xr-x 2 root root 4096 Apr 25 23:08 conf.d -rw-r--r-- 1 root root 1465 Mar 4 21:00 envvars -rw-r--r-- 1 root root 31063 Oct 21 2012 magic drwxr-xr-x 2 root root 4096 Apr 10 01:16 mods-available drwxr-xr-x 2 root root 4096 Apr 10 14:35 mods-enabled -rw-r--r-- 1 root root 773 Apr 28 21:15 ports.conf drwxr-xr-x 2 root root 4096 Apr 26 16:20 sites-available drwxr-xr-x 2 root root 4096 Apr 29 18:31 sites-enabled
The leading "
d" signifies a directory, while "
-" is a file and "
l" is a link. The next 3 characters are the rights of the user (
u), the next 3 are for the group (
g) and the last 3 is that of others (
r = read,
w = write,
x = execute and
- signifies no-rights (e.g.
r-x is read, no write, execute).
The following removes execute rights from user:
chmod u-x DIRECTORY/FILENAME
The following gives others execute rights:
chmod o+x DIRECTORY/FILENAME
The following recursively gives others rights to write and execute:
chmod -R o+rw DIRECTORY/FILENAME
The following recursively removes read and execute rights for group:
chmod -R g-rx DIRECTORY/FILENAME
With the following All get read, write and execute rights:
chmod a=+rwx file
Use the following command to delete all lof files:
sudo rm `find /var/log -type f`
Using Nano, to delete entire content of a file, set cursor at the beginning of the file. Hold CTRL and 6 to set a mark. ALT and SHIFT and T (or try ALT and T) to cut to the end of the file.
The following restarts the cron daemon:
sudo /etc/init.d/cron restart