BASH shell scripting

jackdaw

Hi
Im doing a little script in BASH for emailing files and then deleting them

I have

#! /bin/sh



LOCAL=/root/em_files


cd $LOCAL

for f in *.tif

do 
	if [ $f = "*"]; then
		break #because of no files
	else 
	if [mail_body.txt = "*"]; then
		break #mail body doesn't exist
	
	else 
	mutt -s "[$f]" -a $f emaddress@org.com  < mail_body.txt
	rm -f $f
	fi
done

How can i incorporate an OR in an if stmt ?
and how can i check if a file doesn't exist what i have above

if [mail_body.txt = "*"]; then
		break #mail body doesn't exist

im not sure , i only know that

if [ $f = "*"]; then
		break #because of no files

checks to see if the other files exist ? but what about when i wanna check just one ?

Procasinator

There are plenty of tutorials on the net for bash scripting, give Google a try.

How can i incorporate an OR in an if stmt ?

There is a -o flag - look at http://tldp.org/LDP/abs/html/comparison-ops.html and compound comparison subsection.

and how can i check if a file doesn't exist what i have above

There are various flags for checking files. You might what to use -e (file exists) or -s (file is non-empty). Look at:
http://tldp.org/LDP/abs/html/fto.html

Tobias Greeshman

Procasinator wrote: »

There is a -o flag - look at http://tldp.org/LDP/abs/html/comparison-ops.html and compound comparison subsection.

Just one thing to be careful of here is the (($a < $b)), the double bracket comparison, was introduced by the bash shell and may not be present in sh (original unix shell). And the OP has a shabang line referencing /bin/sh instead of /bin/bash, so that might cause some issues. Also the comparison "$a" < "$b" will only work in bash, and not sh.

brianmc

jackdaw wrote: »

Hi
Im doing a little script in BASH for emailing files and then deleting them

I have

etc..

#!/bin/bash

LOCAL=/root/em_files

if [[ -f $LOCAL/mail_body.txt ]]
then
	echo "Mail Body does not exist" >&2
	exit 1
fi

for FILENAME in $(ls $LOCAL/*.tif)
do
	mutt -s "[$FILENAME]" -a $FILENAME emaddress@org.com < $LOCAL/mail_body.txt
	rm -f $LOCAL/$FILENAME
done

exit 0

I find it's much better in scripts to avoid using "cd" since it's effectively a global attribute of the process and should the script become more complex this will only make it trickier to work with.

As was pointed out earlier, you've added a #! reference to the Bourne shell and not to the Bash shell. For Bourne there would be very few changes from above... feck it actually... here...

I've used "ls" to get the list of filenames for the for loop rather than file name matching so that if the directory is empty we end up with nothing to be processed rather than a value of "*.tif".

#!/bin/sh

LOCAL=/root/em_files

if [ -f $LOCAL/mail_body.txt ]
then
	echo "Mail Body does not exist" >&2
	exit 1
fi

for FILENAME in `ls $LOCAL/*.tif`
do
	mutt -s "[$FILENAME]" -a $FILENAME emaddress@org.com < $LOCAL/mail_body.txt
	rm -f $LOCAL/$FILENAME
done

exit 0

Watch out for spacing around the square brackets in the "if" statement. The first bracket isn't really a trivial bit of syntax it's effectively a command that does comparisons and tests so the remaining part of the line " -e $LOCAL/mail_body.txt ] " is actually a sequence of arguments to a command.

-f is a test to see that a file (specifically a file - not a directory or anything else) exists in the file system.