Shell Programming and Scripting

I think i got it, but i ask thread-o/p to confirm. The presentation of his problem was perhaps a bit off from optimal:

There is ONE file with some database statements:

Code:

CREATE OR REPLACE VIEW DB_V.TAB1 AS SELECT * FROM DB_T.TAB1;
....
CREATE OR REPLACE VIEW DB_V.TAB10 AS SELECT * FROM DB_T.TAB10;
CREATE INDEX TAB1_COL1 ON TAB1 (COL1);
...
CREATE INDEX TAB6_COL1 ON TAB6 (COL1);
CREATE INDEX TAB7_COL1 ON TAB7 (COL1)
...
CREATE INDEX TAB10_COL1 ON TAB10 (COL1);

Now, some of these statements are already processed, others are not. Which are processed is in a second file (the "spool file":

Code:

TAB1_COL1
TAB2_COL1
TAB3_COL1
TAB4_COL1
TAB5_COL1
TAB6_COL1

Thread-o/p wants to be able to restart the (first) command file after it has been stopped and for this (to avoid already done things a second time) comment out all already run commands. This is done by adding a "--" at the beginning of the line. What he was trying to do was to read the spool file line by line and for each line prepend all lines containing the table (?, index?) in question with comment signs.

@Thread-o/p: please tell us if this is correct. If yes, your script was "almost correct", but to prepend a whole line with something you could have done easier:

Code:

while read ITEM ; do
     sed '/'"$ITEM"'/ s/^/-- /' /your/command/file > /your/command/file.tmp
     mv /your/command/file.tmp /your/command/file
done < /path/to/spool/file

I hope this helps.

bakunin

PS: on second thoughts, Dons concerns of course still apply! You have to prevent i.e. "COL1" to trigger changes in lines containing "COL19". Maybe adding a space after "$ITEM" like this

Code:

while read ITEM ; do
     sed '/'"$ITEM"' / s/^/-- /' /your/command/file > /your/command/file.tmp
     mv /your/command/file.tmp /your/command/file
done < /path/to/spool/file

would suffice but to decide that you will have to analyse the command file you are trying to change.

Thank you Ravinder Singh, RudiC, Don Cragun, Bakunin for your inputs. Have used the RudiC's suggestion along with Don's excellent considerations. The error I was facing for

Code:

sed "/$line/ s/^/--/g"

was

Code:

sed: Function TAB1_COL1 s/^/--/g cannot be parsed /

However, when in command prompt when I assign line=TAB1_COL1 and then sed "/$line/ s/^/--/g" gives me the correct result. However, used the awk solution for now. Bakunin, yes, you summarized accurately my requirement. Will give a try of your suggestion

Code:

sed '/'"$ITEM"'/ s/^/-- /'

There is no logical difference between the commands:

Code:

sed "/$line/ s/^/--/g"

and:

Code:

sed '/'"$line"'/ s/^/-- /'

The diagnostic message:

Code:

sed: Function TAB1_COL1 s/^/--/g cannot be parsed /

would be more likely to occur if the slashes around the pattern had been dropped... I.e.:

Code:

sed "$line s/^/--/g"

instead of:

Code:

Code:

sed "/$line/ s/^/--/g"