Hello everyone!
I finally got a chance to play with my Photon from particle.io, and I had been using the dashboard to debug my events..
I have a snipit of code that uses the provided OneWire library to read the temp from all of the sensors attached to my photon, and one by one 'Publish' a key/value pair to the particle API. I was using the OneWire address in hex as the key, and the temp in fahrenheit as the value. This would allow me to later create a mapping of which sensor was located where, but didn't need to be hard-coded into the firmware of the device.
I learned about two things today, both from the particle cli tool: particle subscribe mine and particle serial monitor
particle serial monitor lets me read the Serial.print* statements from my photon if I have it plugged in with a usb cable. I was previously opening up the editor to do this (while actually editing my code in the slick web IDE).
particle subscribe mine is a way to subscribe to all events produced by your devices on your account. Since my events are dynamically named based on the OneWire address, I didn't have a direct name to subscribe to. I'll have to create a service to read in the values from my sensors and log them for later processing.
Happy Hacking!
Showing posts with label CLI. Show all posts
Showing posts with label CLI. Show all posts
Sunday, November 8, 2015
Friday, October 23, 2015
Why is bash-complete so slow!
So, I've been using home-brew for a little while on my macbook, and I noticed that after I installed a few things with it, my tab completion was REALLY slow.... A little poking around was in order.
First I looked in my ~/.bash_profile, and I saw the following
if [ -f $(brew --prefix)/etc/bash_completion ]; then
. $(brew --prefix)/etc/bash_completion
fi
That pointed me in the direction I needed to go... Lets run the subtle command to see where it points!
MacBook-Pro-2:puppet-sandbox dawiest$ brew --prefix
/usr/local
So lets see how many files (and lines) are contained in those files..
MacBook-Pro-2:bash_completion.d dawiest$ ls /usr/local/etc/bash_completion.d/ | wc -l
186
MacBook-Pro-2:puppet-sandbox dawiest$ find /usr/local/etc/bash_completion{,.d/*} |xargs wc -l | grep total
wc: /usr/local/etc/bash_completion.d/helpers: read: Is a directory
25412 total
Holy smokes! 186 files, with 25k lines! No wonder it takes so long!
After I opened up the list of files in the bash_completion.d/ directory, removed the ones I didn't care about (they are all just symlinks pointing back to ../../Cellar/bash-completion/1.3/etc/bash_completion.d/), my auto-complete's in my shell are noticeably faster!
MacBook-Pro-2:puppet-sandbox dawiest$ ls /usr/local/etc/bash_completion.d/ | wc -l
50
MacBook-Pro-2:puppet-sandbox dawiest$ find /usr/local/etc/bash_completion{,.d/*} |xargs wc -l | grep total
wc: /usr/local/etc/bash_completion.d/helpers: read: Is a directory
14115 total
50 files, and 14k lines to execute, but I think I have removed the biggest offenders. I should figure out a way to profile each of the scripts to see how long they each take to source! It may be better to find the biggest offenders, and remove them if they aren't part of your usual command set.
Thursday, October 15, 2015
TiL - remember how to shell quote!
Just the other day, I was doing something over and over.... trying to kill a stubborn tomcat server that wouldn't gracefully die. sudo service tomcat stop just wouldn't cut it.
I was getting tired of repeatedly typing 'ps aux | grep tomcat', copying out the Process id, and passing it to kill -9. Time for some simple automation... an alias!
So, how to find the Process? First, we use ps to display a list of running processes, and the grep utility to select only the lines that contain tomcat.
My command looks something like this
Here is the updated command.
Most important note about the above command.... I initially forgot to use the single quote ('), and I accidentally used the double quote ("). What happens in that case is that your shell will try to do a variable substation, and replace $2 with the variable 2 ( which is usually used when you are passing arguments to a shell script, $0 is the name of the script, $1 is the first argument, $2 is the second, etc...). Since there was nothing in $2, it turned the awk command into 'print', which simply prints the entire line.
Here is the command without output using the wrong quotes.
Now, that will return only the PID... but what to do to it? I need to pass it as an argument to the kill command, so I'll run it in a subshell by putting it between two backpacks (`). I use the -9 argument to force kill to kill it totally. Remember to use sudo if you aren't running as the tomcat user!
My full command now looks like this
Remember to properly quote your shell variables, happy command line fu everyone!
I was getting tired of repeatedly typing 'ps aux | grep tomcat', copying out the Process id, and passing it to kill -9. Time for some simple automation... an alias!
So, how to find the Process? First, we use ps to display a list of running processes, and the grep utility to select only the lines that contain tomcat.
I needed to make sure I was only grabbing the tomcat process. Since I only have the tomcat server being run by the tomcat user, and the output of PS starts with the user who is running the process, I could use a regular expression that matches from the beginning of the line to the word tomcat. To make sure I can use the beginning of line char (^) in my regex, I use the '-E, --extended-regexp' argument.vagrant@client1:~$ ps aux | grep tomcattomcat7 6355 0.9 26.2 1050336 63972 ? Sl 00:37 0:04 /usr/lib/jvm/default-java/bin/java -Djava.util.logging.config.file=/var/lib/tomcat7/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC -Djava.endorsed.dirs=/usr/share/tomcat7/endorsed -classpath /usr/share/tomcat7/bin/bootstrap.jar:/usr/share/tomcat7/bin/tomcat-juli.jar -Dcatalina.base=/var/lib/tomcat7 -Dcatalina.home=/usr/share/tomcat7 -Djava.io.tmpdir=/tmp/tomcat7-tomcat7-tmp org.apache.catalina.startup.Bootstrap start
vagrant 7504 0.0 0.3 10460 940 pts/0 S+ 00:46 0:00 grep --color=autotomcat
My command looks something like this
I then need to pull out the second record, which contains the process ID. For that, I use awk. It simply takes the output and breaks it into 'records', by default it uses whitespace. Using 'print $2' prints out the second record.vagrant@client1:~$ ps aux | grep -E '^tomcat'tomcat7 6355 0.7 25.6 1050336 62424 ? Sl 00:37 0:05 /usr/lib/jvm/default-java/bin/java -Djava.util.logging.config.file=/var/lib/tomcat7/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC -Djava.endorsed.dirs=/usr/share/tomcat7/endorsed -classpath /usr/share/tomcat7/bin/bootstrap.jar:/usr/share/tomcat7/bin/tomcat-juli.jar -Dcatalina.base=/var/lib/tomcat7 -Dcatalina.home=/usr/share/tomcat7 -Djava.io.tmpdir=/tmp/tomcat7-tomcat7-tmp org.apache.catalina.startup.Bootstrap start
Here is the updated command.
vagrant@client1:~$ ps aux | grep -E '^tomcat' | awk '{ print $2 }'6355
Most important note about the above command.... I initially forgot to use the single quote ('), and I accidentally used the double quote ("). What happens in that case is that your shell will try to do a variable substation, and replace $2 with the variable 2 ( which is usually used when you are passing arguments to a shell script, $0 is the name of the script, $1 is the first argument, $2 is the second, etc...). Since there was nothing in $2, it turned the awk command into 'print', which simply prints the entire line.
Here is the command without output using the wrong quotes.
vagrant@client1:~$ ps aux | grep -E '^tomcat' | awk "{ print $2 }"tomcat7 6355 0.6 25.6 1050336 62424 ? Sl 00:37 0:05 /usr/lib/jvm/default-java/bin/java -Djava.util.logging.config.file=/var/lib/tomcat7/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.awt.headless=true -Xmx128m -XX:+UseConcMarkSweepGC -Djava.endorsed.dirs=/usr/share/tomcat7/endorsed -classpath /usr/share/tomcat7/bin/bootstrap.jar:/usr/share/tomcat7/bin/tomcat-juli.jar -Dcatalina.base=/var/lib/tomcat7 -Dcatalina.home=/usr/share/tomcat7 -Djava.io.tmpdir=/tmp/tomcat7-tomcat7-tmp org.apache.catalina.startup.Bootstrap start
Now, that will return only the PID... but what to do to it? I need to pass it as an argument to the kill command, so I'll run it in a subshell by putting it between two backpacks (`). I use the -9 argument to force kill to kill it totally. Remember to use sudo if you aren't running as the tomcat user!
My full command now looks like this
vagrant@client1:~$ sudo kill -9 `ps aux | grep -E '^tomcat' | awk '{ print $2 }'`When successful, this command has no output.
Remember to properly quote your shell variables, happy command line fu everyone!
Saturday, October 3, 2015
Arduino on OS X
Hi everybody!
Quick little blurb today..
Today I installed Arduino using homebrew/cask on my laptop, and was running into a little issue...
chmod: Unable to change file mode on /opt/homebrew-cask/Caskroom/arduino/1.6.5-r5/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude_bin: Operation not permitted
Part of my issue was that I have an unusual homebrew install (installed with my 'admin' user, but my day to day user is not an admin).
I ended up following the steps outlined on this stackexchange post, and it didn't actually solve my problem, but it got my homebrew setup a lot happier for my non-admin user.
Then, I did the last thing any good programmer will do, and actually read what the error message was telling me! The arduino process was trying to chmod a file, which meant that it's mode must be incorrect...
I did an inspection of all the files in the avr/bin/ directory, and none of them had owner OR group execute permissions!
A quick little command fixed up my issue!
I can now load sketches to my Arduino, and connect to the serial port!
Thanks for reading everyone! I hope this helps someone with the same problem!
Quick little blurb today..
Today I installed Arduino using homebrew/cask on my laptop, and was running into a little issue...
chmod: Unable to change file mode on /opt/homebrew-cask/Caskroom/arduino/1.6.5-r5/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude_bin: Operation not permitted
Part of my issue was that I have an unusual homebrew install (installed with my 'admin' user, but my day to day user is not an admin).
I ended up following the steps outlined on this stackexchange post, and it didn't actually solve my problem, but it got my homebrew setup a lot happier for my non-admin user.
Then, I did the last thing any good programmer will do, and actually read what the error message was telling me! The arduino process was trying to chmod a file, which meant that it's mode must be incorrect...
bash-3.2$ ls -la /opt/homebrew-cask/Caskroom/arduino/1.6.5-r5/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude_bin-rw-rw-r-- 1 admin admin 369784 Apr 14 16:30 /opt/homebrew-cask/Caskroom/arduino/1.6.5-r5/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude_bin
I did an inspection of all the files in the avr/bin/ directory, and none of them had owner OR group execute permissions!
A quick little command fixed up my issue!
bash-3.2$ chmod g+x /opt/homebrew-cask/Caskroom/arduino/1.6.5-r5/Arduino.app/Contents/Java/hardware/tools/avr/bin/*
I can now load sketches to my Arduino, and connect to the serial port!
Thanks for reading everyone! I hope this helps someone with the same problem!
Friday, September 18, 2015
s3 ETag and puppet
Hello faithful readers!
Today, I ponder a problem... how to know if I have the latest version of a file from an s3 bucket, and how to get that logic into puppet?
Amazon s3 buckets can contain objects, which contain an ETag... which is sometimes the md5, and sometimes not..
In trying to figure out how to know if I should download an object or not, I was inspired by the s3file module out on the puppet forge.
https://github.com/branan/puppet-module-s3file/blob/master/manifests/init.pp
Notably, this slick shell command to pull out the ETag and compare it to the md5sum of the file..
"[ -e ${name} ] && curl -I ${real_source} | grep ETag | grep `md5sum ${name} | cut -c1-32`"
However, I saw that in my use case, we used aws s3 cp /path/to/file s3://bucketname/key/path/ and our uploads happen as multipart uploads at the low level. this makes our ETag break into multiple parts for files much smaller than the rest of the internet (I think at either 5mb or 15mb boundaries), which makes it not so keen for the above situation.
also, we don't have a publicly available bucket to curl, so we have to replace the curl -I call with a aws s3api head-object --bucket bucketname --key key/path/file.
While playing with the s3api command, I looked at a file I had uploaded previously. When I uploaded it, I had used s3cmd's sync option. I saw the following output.
Today, I ponder a problem... how to know if I have the latest version of a file from an s3 bucket, and how to get that logic into puppet?
Amazon s3 buckets can contain objects, which contain an ETag... which is sometimes the md5, and sometimes not..
In trying to figure out how to know if I should download an object or not, I was inspired by the s3file module out on the puppet forge.
https://github.com/branan/puppet-module-s3file/blob/master/manifests/init.pp
Notably, this slick shell command to pull out the ETag and compare it to the md5sum of the file..
"[ -e ${name} ] && curl -I ${real_source} | grep ETag | grep `md5sum ${name} | cut -c1-32`"
However, I saw that in my use case, we used aws s3 cp /path/to/file s3://bucketname/key/path/ and our uploads happen as multipart uploads at the low level. this makes our ETag break into multiple parts for files much smaller than the rest of the internet (I think at either 5mb or 15mb boundaries), which makes it not so keen for the above situation.
also, we don't have a publicly available bucket to curl, so we have to replace the curl -I call with a aws s3api head-object --bucket bucketname --key key/path/file.
While playing with the s3api command, I looked at a file I had uploaded previously. When I uploaded it, I had used s3cmd's sync option. I saw the following output.
$ aws s3api head-object --bucket bucketname --key noarch/epel-release-6-8.noarch.rpm { "AcceptRanges": "bytes", "ContentType": "binary/octet-stream", "LastModified": "Sat, 19 Sep 2015 03:27:25 GMT", "ContentLength": 14540, "ETag": "\"2cd0ae668a585a14e07c2ea4f264d79b\"", "Metadata": { "s3cmd-attrs": "uid:502/gname:staff/uname:~~~~/gid:20/mode:33188/mtime:1352129496/atime:1441758431/md5:2cd0ae668a585a14e07c2ea4f264d79b/ctime:1441385182" }}
When I manually uploaded the file using aws s3 cp, I saw the following header info on the s3 object
$ aws s3api head-object --bucket bucketname --key epel-release-6-8.noarch.rpm { "AcceptRanges": "bytes", "ContentType": "binary/octet-stream", "LastModified": "Sat, 19 Sep 2015 03:39:13 GMT", "ContentLength": 14540, "ETag": "\"2cd0ae668a585a14e07c2ea4f264d79b\"", "Metadata": {}}
So, the MD5 IS in there... IF I use a program/command that sets it in the metadata.
Back to my problem at hand... how would I know if I already downloaded the file? What are my options?
- Figure out some sort of script to calculate the md5 sum of the file. This would require me assuming the number of multi-part chunks
- Always make our upload process either not use multi-part uploads (keeping the ETag equal to the MD5sum) or use some tool or manually set the metadata to contain an md5sum
- Pull out the ETag value when I download the file, and store an additional file with my downloaded s3 file (e.g. if I have s3://bucket/foo.tar.gz, pull out it's ETag and write it to foo.tar.gz.etag after a successful download)
All three have disadvantages.
#1 - This script has to assume or calculate multi-part upload chunk size. It is explored in some of the answers at this StackOverflow post.
#2 - This requires our uploads to have happened a certain way. If someone circumvents the standard process for uploading (uses a multipart upload, or uploads with the aws s3 cp instead of aws s3api put-object), then we would always download the item.
# 3 - This requires us saving a separate metadata file alongside the file download. If the application we are downloading the file for is sensitive to additional files hanging around, this may interfere. there IS a big plus in this case though.
aws s3api get-object has a helpgul argument....
--if-none-match (string) Return the object only if its entity tag
(ETag) is different from the one specified, otherwise return a 304 (not
modified).
If I use that, the s3 call would skip downloading the file if the ETag matches.
Also, with option 3... how do I do it in puppet? Do I have some clever chaining of exec resources? Do I create a resource type that utilizes the aws-ruby sdk?
Hrm, another post with ideas and options but no solutions.... I'll have to ponder how I should move forward with this, and fuel a future blog post!
Thanks for reading!
Friday, September 4, 2015
Hi everyone...
Felt like installing macvim... according to the internet, it would be as simple as 'brew install macvim'.
Oh, it wants the full XCode package, but I've just installed the CLI tools... lets see if there is a binary package in Cask?
Bingo... thanks Cask folks!
Felt like installing macvim... according to the internet, it would be as simple as 'brew install macvim'.
bash-3.2$ brew install macvimmacvim: A full installation of Xcode.app is required to compile this software.Installing just the Command Line Tools is not sufficient.Xcode can be installed from the App Store.Error: An unsatisfied requirement failed this build.
Oh, it wants the full XCode package, but I've just installed the CLI tools... lets see if there is a binary package in Cask?
bash-3.2$ brew cask install macvim --override-system-vim==> Downloading https://github.com/macvim-dev/macvim/releases/download/snapshot-77/MacVim-snapshot-77.tbz######################################################################## 100.0%==> Symlinking App 'MacVim.app' to '/Users/admin/Applications/MacVim.app'==> Symlinking Binary 'mvim' to '/usr/local/bin/mvim'🍺 macvim staged at '/opt/homebrew-cask/Caskroom/macvim/7.4-77' (1906 files, 35M)
Bingo... thanks Cask folks!
Monday, August 3, 2015
TIL - paste!
Hi everyone!
Today, I was helping a co-worker with a script. He needed to find some set of directories, add /*.jar to the end of each, and put them together in a single line as coma-separated values.
Enter paste! (Funny thought, typing 'man paste' into google turned out much better than I thought it would!)
Say we had a list of all the files on my RaspberryPi's home directory, and we wanted to put them together as a comma separated list... We would simply pipe them through paste with the --delimiters=, and --serial flags set.
$ ls ~/Desktop/ | paste -d, -s
debian-reference-common.desktop,idle3.desktop,idle.desktop,lxterminal.desktop,midori.desktop,ocr_resources.desktop,paste.out,pistore.desktop,python-games.desktop,scratch.desktop,shutdown.desktop,sonic-pi.desktop,wolfram-language.desktop,wolfram-mathematica.desktop,wpa_gui.desktop
Today, I was helping a co-worker with a script. He needed to find some set of directories, add /*.jar to the end of each, and put them together in a single line as coma-separated values.
Enter paste! (Funny thought, typing 'man paste' into google turned out much better than I thought it would!)
Say we had a list of all the files on my RaspberryPi's home directory, and we wanted to put them together as a comma separated list... We would simply pipe them through paste with the --delimiters=, and --serial flags set.
$ ls ~/Desktop/ | paste -d, -s
debian-reference-common.desktop,idle3.desktop,idle.desktop,lxterminal.desktop,midori.desktop,ocr_resources.desktop,paste.out,pistore.desktop,python-games.desktop,scratch.desktop,shutdown.desktop,sonic-pi.desktop,wolfram-language.desktop,wolfram-mathematica.desktop,wpa_gui.desktop
Even though I've been using linux since about 2003, I feel like I stumble onto little nuggets like this pretty often!
Saturday, April 4, 2015
Expecting more - gpg and expect
Hi everyone!
I recently needed to ssh to a machine, with a hard to remember password, and was unable to use ssh keys.
I had seen lots of examples for connecting though ssh that looked something like this...
Can you see something terribly wrong there? The password is stored in plain text in the file! Even setting restrictive file access permissions, that's not a very secure way of handling passwords.
I had read about gpg for storing/extracting secrets when I was learning puppet with the puppet 3 cookbook.
The steps to use gpg are as follows.
But, how do I tie that into an expect script for remotely logging in?
I initially found the exec statement for expect.
If I faked out getting the value directly, it would function as expected
After reading about 50 different stack overflow posts that mostly said 'Why don't you just use ssh keys' or just had examples in plain text, I FINALLY found a clue!
http://ubuntuforums.org/showthread.php?t=1790094
This poor guy got some bad advice, where they aren't using the exec statement (he's just assigning the command string to the password variable), but he had the part that I missed.... the --quiet and --no-tty arguments!
once I added those to my gpg command, everything finally worked!
Here is my final example script -
I recently needed to ssh to a machine, with a hard to remember password, and was unable to use ssh keys.
I had seen lots of examples for connecting though ssh that looked something like this...
#!/usr/bin/expect -f set timeout 60 spawn ssh username@machine1.domain.com expect "Password: " send "Password\r" send "\r" # This is successful. I am able to login successfully to the first machine # at this point, carry on scripting the first ssh session: send "ssh username@machine2.domain.com\r" expect ...
Can you see something terribly wrong there? The password is stored in plain text in the file! Even setting restrictive file access permissions, that's not a very secure way of handling passwords.
I had read about gpg for storing/extracting secrets when I was learning puppet with the puppet 3 cookbook.
The steps to use gpg are as follows.
#generate gpg key
temp@old-laptop:~$ gpg --gen-key
gpg (GnuPG) 1.4.16; Copyright (C) 2013 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
gpg: directory `/home/temp/.gnupg' created
gpg: new configuration file `/home/temp/.gnupg/gpg.conf' created
gpg: WARNING: options in `/home/temp/.gnupg/gpg.conf' are not yet active during this run
gpg: keyring `/home/temp/.gnupg/secring.gpg' created
gpg: keyring `/home/temp/.gnupg/pubring.gpg' created
Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048)
Requested keysize is 2048 bits
Please specify how long the key should be valid.
0 = key does not expire
<n> = key expires in n days
<n>w = key expires in n weeks
<n>m = key expires in n months
<n>y = key expires in n years
Key is valid for? (0)
Key does not expire at all
Is this correct? (y/N) y
You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
"Heinrich Heine (Der Dichter) <heinrichh@duesseldorf.de>"
Real name: John Doe
Email address: jd@JohnDoe.com
Comment: example
You selected this USER-ID:
"John Doe (example) <jd@JohnDoe.com>"
Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
You need a Passphrase to protect your secret key.
gpg: /home/temp/.gnupg/trustdb.gpg: trustdb created
gpg: key CFE3FAA2 marked as ultimately trusted
public and secret key created and signed.
gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0 valid: 1 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 1u
pub 2048R/CFE3FAA2 2015-04-04
Key fingerprint = 5851 BF85 33A2 01E5 895F 0BD2 34B0 F74F CFE3 FAA2
uid John Doe (example) <jd@JohnDoe.com>
sub 2048R/D7422C09 2015-04-04
#make file containing secret - please do it with an editor!
temp@old-laptop:~$ echo "1234" > ~/passfile
#encrypt file
temp@old-laptop:~$ gpg -e -r jd@JohnDoe.com ~/passfile
#remove plaintext file
temp@old-laptop:~$ ls
examples.desktop passfile passfile.gpg
temp@old-laptop:~$ rm passfile
#decrypt file
temp@old-laptop:~$ gpg -d ~/passfile.gpg
You need a passphrase to unlock the secret key for
user: "John Doe (example) <jd@JohnDoe.com>"
2048-bit RSA key, ID D7422C09, created 2015-04-04 (main key ID CFE3FAA2)
can't connect to `/run/user/1000/keyring-WFzMA0/gpg': Permission denied
gpg: can't connect to `/run/user/1000/keyring-WFzMA0/gpg': connect failed
gpg: encrypted with 2048-bit RSA key, ID D7422C09, created 2015-04-04
"John Doe (example) <jd@JohnDoe.com>"
1234
But, how do I tie that into an expect script for remotely logging in?
I initially found the exec statement for expect.
...It just didn't work properly for me. GPG would prompt me for my passphrase, but it would output some notification text and the key to my display, and while it would be stored in the variable, it confused expect and didn't properly spawn my ssh connection.
set password [exec gpg -d passfile.gpg]
...
If I faked out getting the value directly, it would function as expected
...Hrm... so what was I doing wrong? If I ran the same command and grabbed the output and redirected it to a file, it only contained my password.
set password [exec echo 1234]
...
gpg -d passfile.gpg > passfile.out
cat passfile.out
After reading about 50 different stack overflow posts that mostly said 'Why don't you just use ssh keys' or just had examples in plain text, I FINALLY found a clue!
http://ubuntuforums.org/showthread.php?t=1790094
This poor guy got some bad advice, where they aren't using the exec statement (he's just assigning the command string to the password variable), but he had the part that I missed.... the --quiet and --no-tty arguments!
once I added those to my gpg command, everything finally worked!
Here is my final example script -
#!/usr/bin/expect
set pass [exec gpg --decrypt --quiet --no-tty passfile.gpg]
spawn ssh temp@localhost
expect "password:"
send "$pass\r"
interact
Friday, February 27, 2015
Expect the unexpected!
I have been working with linux since Highschool (which isn't as long ago for me as it is for some), and I have just found a new command-line tool!
Expect
I was attempting to automate the 'store user config' process, and the weblogic.Admin way of doing it wasn't behaving(complaining about invalid pad in the key), so I was defaulting back to the WLST command. I ran into the same problem described here. Since in my specific scenario, I needed some environment configuration that didn't translate properly, I needed a way to execute it directly in my bash script.
Using the following WLST script (here's the one from StackOverflow above)
After a coworker suggested "expect", I came up with the following solution...
The expect command will 'spawn' the java process. It will wait until it sees the "y or n" portion of output from the script, when it will then 'send' a y followed by a newline to the program.
The first line, 'set timeout -1' was because creating the key file takes longer then the default timeout in expect, so it would terminate early (leaving behind a 0 length userkey.secure file)
Expect
I was attempting to automate the 'store user config' process, and the weblogic.Admin way of doing it wasn't behaving(complaining about invalid pad in the key), so I was defaulting back to the WLST command. I ran into the same problem described here. Since in my specific scenario, I needed some environment configuration that didn't translate properly, I needed a way to execute it directly in my bash script.
Using the following WLST script (here's the one from StackOverflow above)
#storeUserConfig.py
connect(user1,p@ss,'t3://myhost:9999')
storeUserConfig(userConfigFile='userconfig.secure',userKeyFile='userkey.secure')
disconnect()
exit()yes | java -cp $PATH_TO_WEBLOGIC_JAR weblogic.WLST storeUserConfig.py"
and
java -cp $PATH_TO_WEBLOGIC_JAR weblogic.WLST storeUserConfig.py" << EOF
y
EOF
After a coworker suggested "expect", I came up with the following solution...
#createKeyAndConfig.sh
## Do some stuff to set up the env similar to weblogic's included stopWebLogic.sh
...
CMD="java -cp $PATH_TO_WEBLOGIC_JAR weblogic.WLST storeUserConfig.py"
expect -c "
set timeout -1
spawn \"$CMD\"
expect \"y or n\"
send \"y\r\"
expect eof
"The expect command will 'spawn' the java process. It will wait until it sees the "y or n" portion of output from the script, when it will then 'send' a y followed by a newline to the program.
The first line, 'set timeout -1' was because creating the key file takes longer then the default timeout in expect, so it would terminate early (leaving behind a 0 length userkey.secure file)
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