Scripts

Prevent this script from running if another instance is already running
    
#
# Prevent this script from running if another instance is already running
#
scriptName=`basename $0`
if [ "`echo $0 | cut -c1`" = "/" ]; then
  scriptPath=`dirname $0`
else
  scriptPath=`pwd`/`echo $0 | sed -e s/$scriptName//`
fi
running=`ps -ef | grep $scriptName | wc -l`
if [ $running -gt 2 ]; then
  echo "An instance of $scriptName is already running"
  exit 0
fi

Input/Output Redirections
<    Redirect STDIN from a file
>    Redirect STDOUT to a file overwriting
>>   Redirect STDOUT to a file appending
2>   Redirect STDERR to a file overwriting
&>   Redirect STDERR and STDOUT
2>&1 Redirect STDERR and STDOUT

Variable operations
var=$((7*3))
#increase 1
var=$((var+1))

Number operations
a=5.55
b=7.3
echo $a + $b
----
5.55 + 7.3

echo $a + $b | bc
----
12.85

c=`echo $a + $b | bc`
echo $c
----
12.85

Unix Test conditions
    (man test,  for more info)

  if [ $running -ge 2 ]; then
  echo "Tutto ok"
    else
  echo "da lanciare"
    fi

    -eq True if the integers n1 and n2 are  algebraically equal.
    -ne True if the integers n1 and n2 are not  algebraically equal.
    -gt True if the integer n1 is  algebraically  greater than the integer n2.
    -ge True if the integer n1 is  algebraically  greater than or equal to the integer n2.
    -lt True if the integer n1 is algebraically less than the integer n2.
    -le True if the integer n1 is algebraically less than or equal to the integer n2.

   
Backslash Escaped Characters
See echo in Command list
\c Suppressing trailing newline
\v Vertical Tab
\r Carriage return
\n Newline

For loop classic
for (( i=0; i<4; i++ )) do
  echo $i
done
----
0
1
2
3

For loop seq
for i in $(seq 3) 
do
  echo $i
done
----
1
2
3

While loop classic
read X
echo "OUT:"
while [ $X -le 5 ]
do
  echo $X
  X=$((X+1))
done
-----
3 (<- input)
OUT:
3
4
5

Read user input & "case" loop
read a 
case $a in
 1 ) echo "one" ;;
 2 ) echo "two" ;;
 * ) echo "any other" ;;
esac
exit 0 

Create a file whose size is based on file system %
filename=tmp
perc=85
folder=/myfolder
mbytes=0
kbytes=`df -k | grep ${folder} | awk '{print $2}'`
used=`df -k | grep ${folder} | awk '{print $3}'`
#for ksh
#let "mbytes = 1024 * ($perc * $kbytes / 100 - $used)"
mbytes=`expr $perc \* $kbytes / 100 - $used`
mbytes=`expr $mbytes \* 1024`
mkfile $mbytes $filename
exit 0

Create a date based folder
  #create dir
  dateDir=$1/`date +%Y%m%d`
  echo $dateDir 
  if [ -e $dateDir ]; then
    echo Dest dir alredy exists
  else
    echo Creating dest dir
    mkdir $dateDir
  fi

Check existance of a remote directory
remoteLogin=batch_ch@lmelb003.lmuk.local
remoteDir=/i02-ch/batch_ch/DATA/DWHDATA/`date +%Y%m%d`
#if source dir not exists then exit
srcEx=`ssh ${remoteLogin} ls -l ${remoteDir} | wc -l`
if [ $srcEx -eq 0 ]; then
  echo Source directory does not exists
  exit 0;
fi

Delete files from ls
#40 older files
ls -lt | tail -40 | while read a b c d e f g h nome
    
#Files for a date
ls -l | grep "Jun 09" | while read a b c d e f g h nome

do
echo "deleting "$nome    
rm -rf $nome
done

Delete files older than 3 days
find . -mtime +3 -exec rm -f {} \;

Kill processes
#Substitute the green part
for pid in `ps -ef|grep oracle|grep racg|grep -v grep |awk '{print $2}'`;do kill -9 $pid; done

Sort by folder size in current dir   
  du -k | while read size nome
    do
  if [ $size -ge 22596 ]; then
    echo $size $nome
    echo $size $nome >> /arch_oem/out.txt
  fi
    done
    sort -n out.txt

Replace a string recursively over many files
I want to replace the string "dba.support@fastweb.it" with "fwictopdba.supportlog@fastweb.it"
over many files recursively in all subdirectories

1) Backup files first:
/usr/bin/find . -name *.ksh | /usr/bin/xargs /usr/bin/grep -i "dba.support@fastweb.it"| cut -f1 -d: | while read file
do
  cp $file /tmp/
  echo $file
done

2) (Solaris)perform replace: 
/usr/bin/find . -name *.ksh | /usr/bin/xargs /usr/bin/grep -i "dba.support@fastweb.it"| cut -f1 -d: | while read file;
do
vi $file >/dev/null 2>&1 << !
#case sensitive
:1,%s/dba.support@fastweb.it/fwictopdba.supportlog@fastweb.it/g
:wq
!
done
   
2) (Linux)
/usr/bin/find pum*.ksh | /usr/bin/xargs /usr/bin/grep -i "runsqlplus_with_logging"| cut -f1 -d: | while read file;
do
vi $file >/dev/null 2>&1 << !
#case sensitive
:1,%s/runsqlplus_with_logging/runsubmit/g
:wq
!
done

Wich files contains a string?
    /usr/bin/find . -name *.sql | /usr/bin/xargs /usr/bin/grep -i "alter user" | while read file;
    do
  echo $file
    done

Log all variables passed to system log
#!/bin/ksh
logger "ONS:" $* 

Easy(and brutal) way to synchronize two system dates
Set up root user equivalence, see ssh - Automatic Connection

[setDate.sh]
#!/bin/ksh
d=`ssh node1 "date"`
date -s "$d"

[crontab]
* * * * * /root/setDate.sh > /dev/null 2>&1