UNIX command and scripting reference

Environment control

Output, communication, and help

Process control

Give everyone read and execute permissions to a file

chmod 755 filename

Give everyone full permissions to a file

chmod 777 filename

Displays information about total space and available space on a file system

df

Flags

• -g Displays statistics in units of GB blocks. The output values for the file
  system statistics would be in floating point numbers as value of each unit in
  bytes is significantly high.

• -i Displays the number of free and used i-nodes for the file system; this output
  is the default when the specified file system is mounted.
• -I Displays information on the total number of blocks, the used space, the free
  space, the percentage of used space, and the mount point for the file system.
• -k Displays statistics in units of 1024-byte blocks.
• -m Displays statistics in units of MB blocks. The output values for the file
  system statistics would be in floating point numbers as value of each unit in
  bytes is significantly high.
• -M Displays the mount point information for the file system in the second
  column.
• -P Displays information on the file system in POSIX portable format.
• -s Gets file system statistics from the VFS specific file system helper instead
  of the statfs system call. Any arguments given when using the -s flag must be a
  JFS or Enhanced JFS filesystem mount point or device. The filesystem must also
  be listed in /etc/filesystems.
• -t Includes figures for total allocated space in the output.
• -v Displays all information for the specified file system.

Display the number of files in a directory

ls -lt | wc -l

Display running processes...

for a user

ps -ef | grep username

for an application

ps -ef | grep <application name or part of app name>

Kill a running process

kill <process-id>

to collect the thread dumps use kill -3 <process-id>
to kill the process use kill -9 <process-id>

Get the active connection in web server user

netstat -a|grep -i est*
to get the count of the active connection use
netstat -a|grep -i est*|wc -l

Delete File that have been created before the past 5 Days

During a Support Project you may need to Delete the Logs that have been older than 60 Days
the command for that look like

find /<replace my_Directory> -mtime +5 -print | xargs rm

where mtime is the File last modification time

Determine the last Day of Month

I found this in net.This script is useful in finding the last day of the month.
Sometime it is necessary to run a command or script on the last day of a month.

month=`date +%m`
today=`date +%e`
year=`date +%Y
lastday=`cal $month $year | grep -v "^$" | tail -1 | awk '{print $NF}'`
if [BlueGuru: $today == $lastday ]; then
echo your code runs here
fi

The grep -v command removes the last line of output if it happens to be blank and the awk command prints the last chunk of data on the line.

FTP script tips

The FTP command only give the read write permission to the owner of the file , sometimes it is necessary for the member of the group or the world to read the file or write the file , in this case you will get the File Permission denied error to over come this in your FTP script add this unmask like
This will create the file with rw-rw-rw- permission.
site umask 000

so your FTP scripts will look something like

ftp $1 << FTP_CMD
cd <your destination Folder>
site umask 000
put $fileName1
quit
FTP_CMD;