I want to be a superhero, and also a ninja! Why choose?
Quick snippet, as I was searching for this one today.
You can output both standard and error output to both screen and log file with the below command:
my_command.sh 2>&1 | tee my_command.log
Explanation:
my_command.sh
2>&1
| tee
I’ve been quite busy this whole day with a partially complete database dump and wanted to prepare for tomorrow with some ninja bash voodoo shizzle. I’m doing a braindump here because I know I’ll have forgotten this when I wake up tomorrow 🙂
The command stated below was the first working example I’ve gotten together, please let me know if you know a neater / better solution!
I’ve got two files. The first file contains lines which need to be deleted from the second line (if they exist there) Continue reading “Remove duplicate lines while comparing two files”
This post is mostly a bookmark for myself. I’ve been using search engines way too often to find this command..
The command to remove a host from a knownhosts file without seeing the actual hostname in the knownhosts file is the following:
[code]ssh-keygen -R HOSTNAME[/code]
Continue reading “Remove host from SSH KnownHosts file without seeing the hostname”
Sed is very very powerful, which is a good thing to be aware of.
I was looking to compare the output of a sed command to the original file before I wanted to execute the sed command directly on the file and came across this handy trick.
It works by using temporary named pipes inside the diff command.
Contents of file:
[code title=”contents of numbers.txt:”]
One
Two
Three
Four
Five
[/code]
If I just want to remove the line which begins with “Four”, I can check my sed command like this:
[code title=”Terminal output:”]
joris@beanie ~
$ diff <(sed ‘/Four/d’ numbers.txt) numbers.txt
3a4
> Four
[/code]
Awesome possum, now I know my sed command won’t destroy anything.
This is a fairly handy trick.
I’m always logging in to different servers, which all have a different location for their logs. With this trick you can login and just type “cd logs” from anywhere.
First we will add our directory to the CDPATH variable:
[code language=”Bash”]
joris@badattitude /data/share/my_domain
$ echo $CDPATH
joris@badattitude /data/share/my_domain
$ export CDPATH=/data/share/my_domain
joris@badattitude /data/share/my_domain
$ echo $CDPATH
/data/share/my_domain
[/code]
Then we’ll check if it is working:
[code language=”Bash”]
joris@badattitude ~
$ cd logs
/data/share/my_domain/logs
joris@badattitude /data/share/my_domain/logs
$
[/code]
Awesome, we’ve arrived in our logs directory straight from our homedir!
This article shows how to execute remote commands via ssh, but you’ll send the commands from your own shell.
[code highlight=”1″]
ssh my_server ‘ls -l /home/my_home_dir’
[/code]
This will result in this output:
[code highlight=”1″]
$ ssh ae2 ‘ls -lha ~’
total 36K
drwxr-xr-x 2 joris joris 4.0K Jan 23 11:42 .
drwxr-xr-x. 5 root root 4.0K Jan 23 11:41 ..
-rw-r–r– 1 joris joris 54 Jan 23 11:41 .bash_logout
-rw-r–r– 1 joris joris 507 Jan 23 11:41 .bash_profile
-rw-r–r– 1 joris joris 213 Jan 23 11:41 .bashrc
-rw——- 1 joris joris 51 Jan 23 11:42 .history
-rw-r–r– 1 joris joris 171 Jan 23 11:41 .kshrc
-rw-r–r– 1 joris joris 375 Jan 23 11:41 .profile
-rw-r–r– 1 joris joris 153 Jan 23 11:41 .vimrc
[/code]
What’s even better, is that you can run multiple commands separated with a semi colon, like this:
[code highlight=”1″]
ssh my_server ‘ls -l /home/my_home_dir;whoami’
[/code]
And the best trick is this one, user input with an interactive command, sending input and output back and forth!
[code highlight=”1″]
ssh -t my_server ‘vi ~/.bash_profile’
[/code]
Everybody knows that the java executable is located in /usr/bin/java , but what if you need the JDK / JRE location itself?
Just using “whereis” will not get you there, that will point you to the /usr/bin/java point.
So, let’s find out a but more about /usr/bin/java:
ls -l /usr/bin |grep java
Awesome, this will lead us somewhere, it’s a symlink to /etc/alternatives/java
So let’s do the same there:
ls -l /etc/alternatives/ |grep java
And we’ve hit the jackpot, among the lines here, there’s a bunch of lines pointing us to the JRE location:
As you can see in the screenshit, our java executable within the JRE location is:
/usr/lib/jvm/java-7-oracle/jre/bin/java
Which means the JRE location is:
/usr/lib/jvm/java-7-oracle/jre
I wanted to add a “Bash Here” context entry when I right click on a directory:
This Bash Here would open that directory in Cygwin (mintty).
My current PC is fairly regulated, so without admin rights and thus I can’t use the CHere option which I would normally use.
I just created the registry keys via regedit and that works fine.
You can use two options:
Create a file called cygwin_bash_here.reg with the following contents:
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Classes\Directory] [HKEY_CURRENT_USER\Software\Classes\Directory\shell] [HKEY_CURRENT_USER\Software\Classes\Directory\shell\bashhere] @="Bash Here" [HKEY_CURRENT_USER\Software\Classes\Directory\shell\bashhere\command] @="C:\\cygwin\\bin\\mintty.exe"
Save the file and double click on it to import it to the registry.
Both options will create a context menu item which opens Cygwin at your current windows directory!
This message occurs every time you start your freshly installed Cygwin when you’re logged in as a domain user.
Your group is currently "mkpasswd". This indicates that your gid is not in /etc/group and your uid is not in /etc/passwd. The /etc/passwd (and possibly /etc/group) files should be rebuilt. See the man pages for mkpasswd and mkgroup then, for example, run mkpasswd -l [-d] >> /etc/passwd mkgroup -l [-d] >> /etc/group Note that the -d switch is necessary for domain users.
Important: You need to install Cygwin with the user you are logged in with.
Tip: Remove the word “setup” from the cygwin executable to be able to install it without administrator privileges. (e.g. setup-x64.exe should be renamed to cygwin-x64.exe)
We just need our current user ( mkpasswd -c ) to be sent to the /etc/passwd and /etc/group files, to do this, we use this command:
mkpasswd -c >> /etc/passwd mkgroup -c >> /etc/group
After that, our current account is added to both /etc/passwd and /etc/group and the annoying greeting message is gone!
I wanted to SSH into my home server from my workplace but I couldn’t reach it directly because of the way the network was set up.
As it turns out it is quite easy to do by using the corkscrew program.
Edit ~/.ssh/config and add the following lines:
Host home joris.his.homeserver.com
Hostname joris.his.homeserver.com
User joris
ProxyCommand corkscrew proxyserveraddress proxyserverport %h %p
The most important part is the ProxyCommand, this lets your ssh client know that it should use corkscrew as a proxy to your host. %h means the host of your remote server, %p means the port of your remote server.