Bash script assistance for loop

bkone · 08-17-2021, 09:59 AM

I have a text file that is formatted like this
LDAP ad-group1
LDAP ad-group2
LDAP ad-group3
... etc

I am trying to run this command against all the lines of the text file using this:

Code:

for name in $(cat /tmp/adgroup_file.txt); do mon query ls hosts -c name contact_groups -ct $name; done > output.txt

Nothing is being sent to the output.txt file it is just blank. I tried to add '' around the command 'mon query ls host -c name contact_groups -ct' $name but then I get
-bash: mon query ls hosts -c name contact_groups -ct: command not found

If I manually run

Code:

mon query ls hosts -c name contact_groups -ct 'LDAP ad_group'

I get the information I want. Just trying to automate this a bit as I have over 100 AD groups I need to query.

Ideally it would be nice to have the export of each AD group to have a contact_groups listing in a separate file but just trying to get the basics working first.

pan64 · 08-17-2021, 10:14 AM

would be nice to use code tags, that makes your post more readable. https://www.linuxquestions.org/quest...do=bbcode#code
also you can use shellcheck to find a lot of different issues in shell scripts like this

Turbocapitalist · 08-17-2021, 10:20 AM

Perhaps it is a matter of quoting so the space stays within the option:

Code:

... -ct "$name" ...

Double quotes make sure that the variable $name is expanded before getting passed to the program.

MadeInGermany · 08-17-2021, 11:54 AM

Code:

for name in $(cat /tmp/adgroup_file.txt)

The shell does word-splitting and filename generation here.
The word splitting splits by $IFS that normally is space or tab or newline, and $name gets
LDAP
ad-group1
LDAP
ad-group2
You can split on only newline with

Code:

IFS="
"
set -f # also disable filename generation
for name in $(cat /tmp/adgroup_file.txt); do mon query ls hosts -c name contact_groups -ct $name; done > output.txt

Also this prevents a further word-splitting and filename generation on the $name. Of course quotes can easily prevent this: "$name"

But I recommend a "while read" loop, because the read command defaults to a newline

Code:

while read name; do mon query ls hosts -c name contact_groups -ct "$name"; done < /tmp/adgroup_file.txt > output.txt

michaelk · 08-17-2021, 09:06 PM

for a separate file for each group.

Code:

while read -r name
do
  mon query ls hosts -c name contact_groups -ct "$name" > /some/where/$name_output.txt
done < /tmp/adgroup_file.txt

chrism01 · 08-18-2021, 01:42 AM

Another debugging trick: add

Code:

set -xv

before the first line of your script.
(& do use multiple code lines instead of packing it all onto one - much easier to read/debug)

bkone · 08-19-2021, 07:08 AM

Quote:

Originally Posted by MadeInGermany

Code:

for name in $(cat /tmp/adgroup_file.txt)

The shell does word-splitting and filename generation here.
The word splitting splits by $IFS that normally is space or tab or newline, and $name gets
LDAP
ad-group1
LDAP
ad-group2
You can split on only newline with

Code:

IFS="
"
set -f # also disable filename generation
for name in $(cat /tmp/adgroup_file.txt); do mon query ls hosts -c name contact_groups -ct $name; done > output.txt

Also this prevents a further word-splitting and filename generation on the $name. Of course quotes can easily prevent this: "$name"

But I recommend a "while read" loop, because the read command defaults to a newline

Code:

while read name; do mon query ls hosts -c name contact_groups -ct "$name"; done < /tmp/adgroup_file.txt > output.txt

This provided me with what I was needing the only problem I have with the output is
it the data doesn't tell me what AD group the output belongs to. I was going to try to add something like echo ----"$name"-----; before the done to see if that would at least add the AD group and then under it display the command output so I can easily review it.

I tried using what the other member suggested with breaking out the files so each AD group would have a separate file that listed the output within the individual files but after running nothing was presented.

michaelk · 08-19-2021, 08:30 AM

Quote:

I tried using what the other member suggested with breaking out the files so each AD group would have a separate file that listed the output within the individual files but after running nothing was presented.

Unfortunately I have no way of actually testing the script so you would need to be to do some rudimentary debugging as suggested by chrism01. About the only obvious syntax error would be to add quotes around

Code:

/some/where/"$name"_output.txt

to prevent word splitting. You did not indicate there were any errors when you tried my script so it is difficult for me to fix. I assume that you realized that /some/where is not an exact path and would you would see an error message...

MadeInGermany · 08-20-2021, 12:12 AM

You want to print the group name?
One way is

Code:

while read name; do echo ----"$name"-----; mon query ls hosts -c name contact_groups -ct "$name"; done < /tmp/adgroup_file.txt > output.txt

A multi-line script is better readable:

Code:

while read name
do
  echo "----$name-----"
  mon query ls hosts -c name contact_groups -ct "$name"
done < /tmp/adgroup_file.txt > output.txt