The following script assumes that /bin/sh is a Posix-compatible shell.
If the raw read is successful then it has got a record, then the record is tested for being zero (empty, null).
The script takes a file name as argument, otherwise reads from stdin.
For academic interest, the following works identically because the if ... fi is a block where input and output can be redirected.
The difference is, that the input file is open throughout the block, so another read in the block would read the next line.
Last edited by MadeInGermany; 06-29-2016 at 04:56 PM..
Okay i've got some code which reads a text file and loops through it and there a few if statements inside where one is failing (the one bolded).
Basically the acc column contains a list of three digit access codes, some though have null records (i.e nothing in the field) so what I want to do is... (3 Replies)
Hi
Wrote the below script to identify the empty directories ,when executing the below showing that directory is not empty but the directories are empty.Please help to identify the empty directories
33 is not empty
33 is not empty
33 is not empty
33 is not empty
for file in `find .... (5 Replies)
Hi,
I need to check for value not equal (<>) to 21 and not equal empty or null values.
Please modify this script
if
then
echo "$VALUE,$BSC_NAME,$BSC_ID" > $OUT_FILE/power_up.out
end if
TQ (5 Replies)
hi
I m executing a shell script in which records are to be fetched from a table. If the sql that is running empty result set it is displaying "table null is empty !". I dont want this msg on the standard output. COuld you please help me in this regard (3 Replies)
Hi all
I have a file that i'm running and exec(cat ./dat) against..and putting its contents into any array, then doing an exploding the array into a multi-dimension array...
The 15 multi-dimensional arrays have elements that are null/empty, I would like to remove/unset these elements and then... (2 Replies)
hi
i have record looks like below
1,US
I want to add empty field to the record as below
1, , , ,US
how i can do it using awk ?
i tried with awk its not working
awk '{ print $1", ,"$2 }' filename > file 1 (2 Replies)
Hello,
My script has a trailer record(TR).
Now I need to implement a logic, if TR is missed on the file it should generate me an email stating TR was not on the file..
Kindly help. (15 Replies)
I am trying to use awk to identify and print out records in fields that are empty along with which line they are in. I hope the awk below is close, it runs but nothing results. Thank you :).
awk
awk -F'\t' 'FNR==NR ~ /^*$/ { print "NR is empty" }' file
file
123 GOOD ID 45... (3 Replies)
Hi All
My requirement is to find the null values in particular column of a file and reject it in case if it contains null values. But the challenge is that I want a common command which can be used across different file, as the position of the column we need to check for different file may get... (14 Replies)
I am working an some if then statements for a script.
I want to be able to check for alpha characters or empty out put then exit out.
if ]];
echo "Serial Number Invaild"
then exit 3;
How do I account if the output is empty or null in this in this statement.
Many thanks (6 Replies)
Discussion started by: andysensible
6 Replies
LEARN ABOUT POSIX
escape
escape(1) Mail Avenger 0.8.3 escape(1)NAME
escape - escape shell special characters in a string
SYNOPSIS
escape string
DESCRIPTION
escape prepends a "" character to all shell special characters in string, making it safe to compose a shell command with the result.
EXAMPLES
The following is a contrived example showing how one can unintentionally end up executing the contents of a string:
$ var='; echo gotcha!'
$ eval echo hi $var
hi
gotcha!
$
Using escape, one can avoid executing the contents of $var:
$ eval echo hi `escape "$var"`
hi ; echo gotcha!
$
A less contrived example is passing arguments to Mail Avenger bodytest commands containing possibly unsafe environment variables. For
example, you might write a hypothetical reject_bcc script to reject mail not explicitly addressed to the recipient:
#!/bin/sh
formail -x to -x cc -x resent-to -x resent-cc
| fgrep "$1" > /dev/null
&& exit 0
echo "<$1>.. address does not accept blind carbon copies"
exit 100
To invoke this script, passing it the recipient address as an argument, you would need to put the following in your Mail Avenger rcpt
script:
bodytest reject_bcc `escape "$RECIPIENT"`
SEE ALSO avenger(1),
The Mail Avenger home page: <http://www.mailavenger.org/>.
BUGS
escape is designed for the Bourne shell, which is what Mail Avenger scripts use. escape might or might not work with other shells.
AUTHOR
David Mazieres
Mail Avenger 0.8.3 2012-04-05 escape(1)