Tag Archives: Linux

SFTP User Creation CentOs

Step 1. Crate Group
groupadd sftponly

Step 2. Create user account
useradd -d /home/sftp/MYUSER -s /bin/false -G sftponly MYUSER

Step 3. Create a password for your username.
passwd MYUSER

Step 4. Ensure the following line is commented out in your sshd configuration file ( File Location: /etc/ssh/sshd_config )
# Edit the sshd_config file which holds the SSH/SFTP configuration
vi /etc/ssh/sshd_config
# Ensure this below Line has a hash symbol, # in front of it
#Subsystem sftp /usr/lib/openssh/sftp-server
# Ensure that this below line is added directly below the line you just commented out with a hash symbol #
Subsystem sftp internal-sftp

Step 5. Add the following to the bottom of the same file (it must be at the very bottom)
Match Group sftponly
ChrootDirectory %h
X11Forwarding no
AllowTCPForwarding no
ForceCommand internal-sftp

Step 6. Test the changes with sshd before restarting the service, please note it’s important you do this correctly, or may break your sshd configuration
sshd -t
service sshd restart

Step 7. Give proper ownership to the newly created folder
chown root:root /home/sftp/MYUSER

Step 8. Test SFTP credential is working:
# Connect to SFTP using the myuser, replace myuser with the user you’ve chosen
sftp myuser@localhost
myuser@localhost’s password:


Disk Space Usage CentOs Linux

Check File System Disk Space Usage : df
Display Information of all File System Disk Space Usage : df -a
Show Disk Space Usage in Human Readable Format : df -h
Display Information of /home File System : df -hT /home
Display Information of File System in Bytes : df -k
Display Information of File System in MB : df -m
Display Information of File System in GB : df -h
Display File System Inodes : df -i
Display File System : df -T
Include Certain File System : df -t ext
Exclude Certain File System : df -x ext
Display Information of df Command: df --help


Apache Directives

Apache directives are a set of rules which define how your server should run, number of clients that can access your server, etc. you can change them by editing the httpd.conf and related files to meet your requirements

Below given are the some of the important directives

  • Alias
  • AliasMatch
  • CheckSpelling
  • DocumentRoot
  • ErrorDocument
  • Options
  • ProxyPass
  • ProxyPassReverse
  • ProxyPassReverseCookieDomain
  • ProxyPassReverseCookiePath
  • Redirect
  • RedirectMatch
  • RewriteCond
  • RewriteRule
  • ScriptAlias
  • ScriptAliasMatch
  • UserDir

Apache mod_rewrite

This module uses a rule-based rewriting engine (based on a regular-expression parser) to rewrite requested URLs on the fly. It supports an unlimited number of rules and an unlimited number of attached rule conditions for each rule, to provide a really flexible and powerful URL manipulation mechanism. The URL manipulations can depend on various tests, of server variables, environment variables, HTTP headers, or time stamps. Even external database lookups in various formats can be used to achieve highly granular URL matching.

This module operates on the full URLs (including the path-info part) both in per-server context (httpd.conf) and per-directory context (.htaccess) and can generate query-string parts on result. The rewritten result can lead to internal sub-processing, external request redirection or even to an internal proxy throughput.


Apache CheckSpelling

This directive enables or disables the spelling module. When enabled, keep in mind that

  • the directory scan which is necessary for the spelling correction will have an impact on the server’s performance when many spelling corrections have to be performed at the same time.
  • the document trees should not contain sensitive files which could be matched inadvertently by a spelling “correction”.
  • the module is unable to correct misspelled user names (as in http://my.host/~apahce/), just file names or directory names.
  • spelling corrections apply strictly to existing files, so a request for the <Location /status> may get incorrectly treated as the negotiated file “/stats.html”.

mod_speling should not be enabled in DAV enabled directories, because it will try to “spell fix” newly created resource names against existing filenames, e.g., when trying to upload a new document doc43.html it might redirect to an existing document doc34.html, which is not what was intended.