if/else with an empty file... Post: 302722721

Sponsored Content

Top Forums Shell Programming and Scripting if/else with an empty file... Post 302722721 by Imnewtothis on Sunday 28th of October 2012 11:24:08 AM

10-28-2012

Registered User

if/else with an empty file...

Hi there,

I'm just starting out with shell scripting and I'm trying to make a test where the script will basically run yum check-update to find out if the server has any available and if it does it e-mails me but if not it will just stop there.

I have it working if there are actually updates to be applied it works well. However, when I'm checking to see if the file is empty it seems to be sending out the e-mail anyway. The script I'm using is:

Code:

#!/bin/bash
/usr/bin/yum check-update | tail -n +3 > newUpdates.txt

SUBJECT="$HOSTNAME needs to be updated"
EMAIL="someemail@domain.com"
EMAILMSG="/root/newUpdates.txt"

if test "$EMAILMSG" = null
then
        rm -rf /root/newUpdates.txt
        exit
else
        /bin/mail -s "$SUBJECT" "$EMAIL" < $EMAILMSG
        rm -rf /root/newUpdates.txt
fi

So I was just running the command and then trying to strip out the first few lines that I'm sending to my temp file because it will have stuff like "Connecting to RedHat Network, etc, etc" and then if it's blank I just want to exit, but if not it should just list the updates.

Can anyone give me some guidance here??

Imnewtothis

View Public Profile for Imnewtothis

Find all posts by Imnewtothis

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

empty file in hp-ux

Hi, I need your help. How can I create an empty filename with a specific size, in hp-ux? Regards, Mizi

2. Shell Programming and Scripting

How to empty a file(already created)

What is the command to empty an already existing file. please provide me.i used Touch cmd to empty the file.but it changing the time only.

3. Shell Programming and Scripting

File is not empty?

How do I check to make sure a file is not zero bytes? Something like: if then ?????

4. UNIX for Dummies Questions & Answers

how to find empty folders without using -empty

hi all: my solaris FIND does not support find myFolder -type d -empty how can i find the empty folders? thanks!

5. UNIX for Dummies Questions & Answers

Trying to empty file using > but the file size increasing when next append

AIX 5.3 / KSH I have a Java application which creates a log file a.log. I have a KSH script which does the following action cp a.log /directory2/b.log > a.log After this the file size goes to 0 as per "ls -l" Then next time when the application writes into this file, the file size...

6. Shell Programming and Scripting

how to see if the file is empty or not?

hi how can I determine, if a file is empty or not?I am using read line clause. The script should be like: while read line do if(file is empty) then; ...... done < $blacklist

7. UNIX for Dummies Questions & Answers

Getting same exit status for empty and non empty file

Hi All, I am checking for a empty input file to do some further action , but I am getting exit status 0 in both the cases , for empty and non empty file both. The value of $? is coming 0 in if part also and else part too. #!/bin/ksh if ]; then echo "data" # exit 0 echo "$?" else...

8. Shell Programming and Scripting

while file is empty

how can i use while loop ? while file is empty do.... if not empty do ..... in bash

9. Shell Programming and Scripting

Empty out the file

Hi All, I have a piece of perl code in which I DON'T want to delete a file rather empty out the contents, here is the code - if ( unlink("$opt_b") == 1 ) { print_log( "$opt_b deleted", 1 ); }else { print_log( "Could not delete $opt_b:$!", 1 ); ...

10. Shell Programming and Scripting

awk to reformat output if input file is empty, but not if file has data in it

The below awk improved bu @MadeInGermany, works great as long as the input file has data in it in the below format: input chrX 25031028 25031925 chrX:25031028-25031925 ARX 631 18 chrX 25031028 25031925 chrX:25031028-25031925 ARX 632 14...

LEARN ABOUT OPENSOLARIS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The following default shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/ksh93, /bin/pfcsh, /bin/pfksh, /bin/pfsh,
       /bin/sh, /bin/tcsh, /bin/zsh, /sbin/jsh, /sbin/sh, /usr/bin/bash, /usr/bin/csh, /usr/bin/jsh, /usr/bin/ksh, /usr/bin/ksh93, /usr/bin/pfcsh,
       /usr/bin/pfksh, /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh, and /usr/sfw/bin/zsh. /etc/shells overrides the default list.

       Invalid shells in /etc/shells could cause unexpected behavior, such as being unable to log in by way of ftp(1).

FILES

       /etc/shells    list of shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.11							    20 Nov 2007 							 shells(4)

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

empty file in hp-ux

Discussion started by: Mizi

2. Shell Programming and Scripting

How to empty a file(already created)

Discussion started by: laknar

3. Shell Programming and Scripting

File is not empty?

Discussion started by: lesstjm

4. UNIX for Dummies Questions & Answers

how to find empty folders without using -empty

Discussion started by: lasse