Need help to understand ksh script

04-15-2011

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Need help to understand ksh script

Hi All,

I have a ksh script & would like to understand mening of below lines in script,

Starting lines of script is as below,

Code:

#!/bin/ksh
#%W% %I% %D% %T% ---- ???
#%W%G --- ???
 
num_ctrl_files=0
OS=`uname`
if [ "$OS" = "SunOS" ]
then
//g' | egrep -v '(.sh:|.ksh:)' | sed 's/^.*://g' | sed 's/^M//g' | grep -v '^[ s]*#' | egrep -i '(.dat|.ctl)' | sed -e 's/^.*=//g' -e 's/,/ /g' -e 's/;/ /g' -e 's/"//g' | tr ' ' '\n' | sed 's/[    ]*//g' | sed '/^$/d' | sort -u | nawk -F"/" '{print $NF}' > $FILE

Please help me to understand above.

Last edited by Franklin52; 04-15-2011 at 05:22 AM.. Reason: Please use code tags

gr8_usk

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04-15-2011

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Oh my... ok, let me give it a shot:

Code:

#!/bin/ksh
#%W% %I% %D% %T% ---- these are comments (starting with #)
#%W%G --- they don't do anything

The beginning of this line here:

Code:

//g'

Seems like something's missing there. To me it looks like the end of some global substitution using sed, something like

Code:

 sed 's/delete_this_pattern//g'

Furthermore, you don't have any input specified there... Where is the data, that these filters operate on, coming from? A file? Pipe? It's gonna want input from stdin...
if statement needs to be closed with 'fi'.

Now for the filters alone, they don't look extremely difficult to understand.

[CODE]egrep -v '(.sh:|.ksh

'[/CODE] is gonna skip lines that contain '.sh:' alebo '.ksh:'
The second filter

Code:

sed 's/^.*://g'

will erase everything before the last colon, including the colon itself. 'g' at the end is not needed.The third filter:

Code:

sed 's/^M//g'

will erase all characters "^M". (these can be seen as delimiters in some windows files.)

Fourth:

Code:

grep -v '^[ s]*#'

will skip (not print for further processing) lines that start with a space or letter 's' present zero or more times and a pound sign. E.g. a line like this:

Code:

sss ss s#something

would be skipped. The line

Code:

sss ttt ff#blah

would not be skipped (there are other chars before pound sign). The line has to contain the pound sign, to be skipped. The next filter

Code:

egrep -i '(.dat|.ctl)'

will keep only lines with '.dat' or .ctl, case insensitive (e.g. '.cTl' would be matched)

This long filter:

Code:

sed -e 's/^.*=//g' -e 's/,/ /g' -e 's/;/ /g' -e 's/"//g'

has four parts: 1. it erases everything before an equal sign, including.
2. changes all commas to spaces
3. changes all semicolons to spaces
4. erases all double quotes.

This filter

Code:

tr ' ' '\n'

Will change (translate) all spaces into newlines

This one

Code:

sed 's/[    ]*//g'

will erase all spaces (there are none by this time)
This

Code:

 sed '/^$/d'

will erase all empty lines.
And finally,

Code:

sort -u | nawk -F"/" '{print $NF}'

will sort the output lines, printing only the first occurence, if there are multiple same lines; and print only the part of the string after the last slash (-F"/" use slash as delimiter; print $NF, print last field).
The output is gonna be written into file $FILE, which, if exists is gonna get overwritten.

Search for "sed regular expressions" for further explanations.

This script is incomplete, and won't work as is.

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Hi Mirni,

First up all thanks as lot for your quick reply to me.

Even I wondered about the same thing when I saw this code first time that from where it is getting input.

To put nmore focus on this, there is one function & into that function this code is present. Please see below code from begining,

Code:

sybSearch()
{
## changing current directory to that of the specified tree.
cd $TREE
cnt=`find ./ -name INSTALL\* -print -follow  2>/dev/null | wc -l | awk '{print $1}'`
if [ $cnt = 0 ]; then
        echo "\n============================================================================================" > $REPORT
        echo "There is no *INSTALL* file in this Package, please create one and resubmit your Package.." >> $REPORT
        echo "============================================================================================\n" >> $REPORT
        mailx -s "Scan Host: $HOST Tree: $TREE" "$MAILSTR" < $REPORT
        exit $VIOLATION
fi
## Preparing TEMP file
cat <<! > $TEMPSYB
[#]*use[#]*master[#]*$
[#]*use[#]*GDMGAdmin[#]*$
[#]*use[#]*GDMGSecurity[#]*$
[#]*use[#]*sybsecurity[#]*$
[#]*use[#]*sybsystemprocs[#]*$
[#]*use[#]*SEMSAuditDb[#]*$
sp_addlogin[#]*
sp_adduser[#]*
sp_addalias[#]*
sp_dropuser[#]*
sp_dropalias[#]*
sp_droplogin[#]*
sp_locklogin[#]*
sp_addgroup[#]*
sp_modifylogin[#]*
sp_changegroup[#]*
sp_addrole[#]*
sp_addrolemember[#]*
sp_droprole[#]*
^[#]*create[#]*role[#]*
^[#]*create[#]*database[#]*
[#]*grant.*to[#]*public[#]*
[#]*revoke.*from[#]*public[#]*
!
#[#]*grant.*to[#]*public[#]*$
#[#]*revoke.*from[#]*
###############################
#### Get list of all Tables
###############################
//g' | egrep -v '(.sh:|.ksh:)' | sed 's/^.*://g' | sed 's/^M//g' | grep -v '^[ /]*#' | egrep -i '(.dat|.ctl)' | sed -e 's/^.*=//g' -e 's/,/ /g' -e 's/;/ /g' -e 's/"//g' | tr ' ' '\n' | sed 's/[    ]*//g' | sed '/^$/d' | sort -u | awk -F"/" '{print $NF}' > $FILE
num_ctrl_files=0
OS=`uname`
if [ "$OS" = "SunOS" ]
then
//g' | egrep -v '(.sh:|.ksh:)' | sed 's/^.*://g' | sed 's/^M//g' | grep -v '^[ s]*#' | egrep -i '(.dat|.ctl)' | sed -e 's/^.*=//g' -e 's/,/ /g' -e 's/;/ /g' -e 's/"//g' | tr ' ' '\n' | sed 's/[    ]*//g' | sed '/^$/d' | sort -u | nawk -F"/" '{print $NF}' > $FILE
        num_ctrl_files=`wc -l $FILE | nawk '{print $1}'`
else
//g' | egrep -v '(.sh:|.ksh:)' | sed 's/^.*://g' | sed 's/^M//g' | grep -v '^[ s]*#' | egrep -i '(.dat|.ctl)' | sed -e 's/^.*=//g' -e 's/,/ /g' -e 's/;/ /g' -e 's/"//g' | tr ' ' '\n' | sed 's/[    ]*//g' | sed '/^$/d' | sort -u | awk -F"/" '{print $NF}' > $FILE
        num_ctrl_files=`wc -l $FILE | awk '{print $1}'`
fi

gr8_usk

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It still looks incomplete. What is done with the file $TEMPSYB?
How is the function sybSearch() called?

mirni

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Please find below code where the function is getting called,

Code:

###################
# Main Body
###################
if [ $RDBMS = "Sybase" ]
then
sybSearch
awk '{
 if (index($0,">>>>CODE VIOLATION") > 0){i=1; t="\n"$0;}
 else
 {if (i==1){print t;i=0}; print $0;}
}' $TEMPRPT1 > $DDLSREPORT
fi

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That $TEMPSYB file, that looks like instructions to a database server. Have you found what is done with this file?
I suspect, it was passed on to the db server, and the output is to be run through the filters.

mirni

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I really don't understand how this <//g'> works !!!

One more thing ... when I executed the script with "set -x " this line starting with //g' executing something like as follows ... " //ged s/"

gr8_usk

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