I have a script that takes an option for server pools to run the script against. The option is given as a comma separated list (ie, -p 201,204,301).
I'm using eval and brace expansion to get those pool numbers into an array. It works fine unless only 1 pool number is given. Here's the code:
If multiple pools given:
If single pool given:
So if a single pool is given it leaves the braces around it which is bad. I could do a test of $1 to see if there are any commas and process it different if there aren't but I was wondering if there's a better solution than that. Also wondering if how I handled getting the pool numbers into an array was the best way to do it (eval & brace expansion).
I'm in the habit of using the following type of loop structure:
for num in `seq $1 $2`
do
command
doneWhile `seq $1 $2` is not exactly a huge resource hog, I would like to learn a better way. It seems that brace expansion is a good way to go:
for num in {3..10}The problem, though, is... (2 Replies)
i write a batch file , here is the content.
dirname='date +%Y-%m-%d'
mkdir dirname
but it doen's work, it just create a folder named date and +%Y-%m-%d.
i have tried run the command seperately in the bash prompt. after the first
sentence executed , i use $dirname to watch the value of... (4 Replies)
So, I was bored on the train today, and was thinking of ways to loop through elements of an array. I came up with the following simple script, but it doesn't work as brace expansion doesn't seem to work with variables. Is there something I'm missing, or does the shell just not work like this?
... (4 Replies)
This is what I have in my directory.
$ ls
test1.txt test2.txt test3.txt test4.txt test5.txt test_script.sh
This is what my shellscript looks like.
#!/bin/bash
for filename in /shell_expansion/*.txt; do
for ((i=0; i<=3; i++)); do
echo "$filename"
... (5 Replies)
Hello.
I cannot write a command without using eval.
Any help is welcome
Note 1 : What does the function SOMETHING has no importance.
Note 2 : What does the command find has no importance.
It is an expansion variable problem : where to put or or or anythings else
What works (FILTRE_1... (8 Replies)
I have made the following examples that print various parameter expansions
text: iv-hhz-sac/hpac/hhz.d/iv.hpac..hhz.d.2016.250.070018.sac
(text%.*): iv-hhz-sac/hpac/hhz.d/iv.hpac..hhz.d.2016.250.070018
(text%%.*): iv-hhz-sac/hpac/hhz
(text#*.): d/iv.hpac..hhz.d.2016.250.070018.sac... (2 Replies)
#!/bin/bash
SNMPW='/usr/bin/snmpwalk'
while read h i
do
loc=$($SNMPW -v3 -u 'Myusername' -l authPriv -a SHA -A 'Password1' -x AES -X 'Password2' $i sysLocation.0 2>/dev/null)
loc=${loc:-" is not snmpable."}
loc=${loc##*: }
loc=${loc//,/}
echo "$i,$h,$loc"
done < $1
My question is ... ... (1 Reply)
I am trying to become more fluent with the interworking of bash and minimize the number of external calls.
Sample Data. This will be the response of the snmp query.
SNMPv2-MIB::sysName.0 = STRING: SomeHostName
SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.1745... (5 Replies)
Hello All,
Could you please do help me here as I would like to perform parameter expansion in shell over a parameter expansion.
Let's say I have following variable.
path="/var/talend/nat/cdc"
Now to get only nat I could do following.
path1="${path%/*}"
path1="${path1##*/}"
Here... (8 Replies)
Discussion started by: RavinderSingh13
8 Replies
LEARN ABOUT DEBIAN
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)