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The biggest advantage of this over the functions is that it is portable.
In this case it's better do to use the dedicated tool
Usage: cmdfu hello world
I did not know this, i'd like to share...
Create a persistent SSH connection to the host in the background. Combine this with settings in your ~/.ssh/config:
All the SSH connections to the machine will then go through the persisten SSH socket. This is very useful if you are using SSH to synchronize files (using rsync/sftp/cvs/svn) on a regular basis because it won't create a new socket each time to open an ssh connection.
Read 32GB zero's and throw them away.
How fast is your system?
If you use Mac OS X or some other *nix variant that doesn't come with ssh-copy-id, this one-liner will allow you to add your public key to a remote machine so you can subsequently ssh to that machine without a password.
Also works with:
chgrp --reference file1 file2
chown --reference file1 file2
Directly attach a remote screen session (saves a useless parent bash process)
If you enable multiuser, then you can permit others to share your screen session. The following conditions apply:
1. screen must be suid root;
2. "multiuser on" must be configured in ~/.screenrc;
3. control the others user(s) access with "aclchg":
# ----- from ~/.screenrc-users -----
aclchg someuser +rx "#?" #enable r/o access to "someuser"
aclchg someuser -x "#,at,aclchg,acladd,acldel,quit" # don't allow these
aclchg otheruser +rwx "#?" # enable r/w access to "otheruser"
aclchg otheruser -x "#,at,aclchg,acladd,acldel,quit" # don't allow them to use these commands
After doing this (once), you start your session with:
Then, the other user can join your terminal session(s) with youruserid:
$ screen -r youruserid/
Note: the trailing "/" is required.
Multiple users can share the same screen simultaneously, each with independent access controlled precisely with "aclchg" in the ~/.screenrc file.
I use the following setup:
# default screenrc on any host
Then, the base configurations are in ~/.screenrc-base; the host-specific configurations are in ~/.screenrc-$HOST, and the user configurations are in ~/.screenrc-users.
The host-specific .screenrc file might contain some host-specific screen commands; e.g.:
screen -t 'anywhere' /bin/tcsh
screen -t 'anywhere1' /bin/tcsh
The .screenrc-base contains:
## I find typing ^a (Control-a) awkward. So I set the escape key to CTRL-j instead of a.
termcapinfo xterm* ti@:te@:
Same as http://www.commandlinefu.com/commands/view/5876, but for bash.
This will show a numerical value for each of the 256 colors in bash. Everything in the command is a bash builtin, so it should run on any platform where bash is installed. Prints one color per line. If someone is interested in formatting the output, paste the alternative.
You can get one specific line during any procedure. Very interesting to be used when you know what line you want.
Of course you need to be able to access host A for this ;-)
'dpkg -S' just matches the string you supply it, so just using 'ls' as an argument matches any file from any package that has 'ls' anywhere in the filename. So usually it's a good idea to use an absolute path. You can see in the second example that 12 thousand files that are known to dpkg match the bare string 'ls'.
Good for one off jobs that you want to run at a quiet time. The default threshold is a load average of 0.8 but this can be set using atrun.
This command shows the various shortcuts that can be use in bash, including Ctrl+L, Ctrl+R, etc...
You can translate "\C-y" to Ctrl+y, for example.
run 'nc yourip 5000', 'nc yourip 5001' or 'nc yourip 5002' elsewhere will produce an exact same mirror of your shell. This is handy when you want to show someone else some amazing stuff in your shell without giving them control over it.
Remove security from PDF document using this very simple command on Linux and OSX. You need ghostscript for this baby to work.
The empty file /forcefsck causes the file system check fsck to be run next time you boot up, after which it will be removed.
This works too:
The Linux kernel uses unused memory in caches. When you execute "free" you never get the "real" available memory.
parse `lsmod' output and pass to `dot' drawing utility then finally pass it to an image viewer