Favorite Unusual Command

[wormser]

Do you have a command that is unusual that most users are unaware of or one that is used in an unusual way. Post any strange tips and tricks. Maybe it is a couple of commands put together. Just anything that is cool that others might find handy, I will start.

chattr -i file

Chattr with the -i switch sets an immutable bit. These are attributes to be added to the existing attributes of the files. A file with the ‘i’ attribute cannot be modified, it cannot be deleted or renamed,

lsattr file

Lsattr displays the chattr permissions.

Post'em.

[blithen]

free -m

It shows the ram usage.

[Hallvor]

[hallvor@localhost ~]$ df
Filesystem Size Used Avail Use% Mounted on
/dev/hdb1 11G 3,8G 6,1G 39% /
/dev/hdb3 101G 72G 25G 75% /mnt/hdb3
/dev/sda1 230G 92G 127G 43% /mnt/sda1
[hallvor@localhost ~]$

[odiseo77]

I don't think these are unusual or something, but are interesting (at least to me):

history
history | grep -i <some piece of some command you forgot>

As many of you surely know, the history command displays the last nn commands used. If you remember a part of a command you want to use now, but you don't remember the whole command with its arguments, etc., you can type the last command I typed before and it will give you the command.

Also:

!command_name

Will execute the last command_name used with all it's arguments (useful when you want to use a command used before, which has a long piece of arguments, pipes, etc. Also usefull for repetitive tasks).

tail -f some_file

The tail command shows the last 10 lines of a file (although I think you can tell it to show more (or less) lines). The -f option leaves the file opened as it grows (useful to monitor log files quickly as they grow).

And so on. I'm sure there are lots of useful and unusual commands few people know about

[p_quarles]

Useful:

du /path/to/dir

Summarizes the total disk space usage of the target directory.

Unusual:

kdontchangethehostname

Informs KDE about hostname changes.

[InfinityCircuit]

I don't know how unusual this is, but I certainly use variations on it a lot. Let's say i'm running sidux and I want to remove all metapackages associated with the name "sidux-686"

dpkg -l  | egrep *sidux-686 | cut -c 8- | cut -c -43 | xargs sudo dpkg -P

I'm old-fashioned.

[herbster]

Dunno if unusual, but sometimes if I know the full objective I'll just put everything on one line:

cd Desktop && tar cjf stuff.tar files && mv stuff.tar /media/backup && cd /media/backup && rsync -avz stuff.tar host@sshserver:backup/

Hitting the "&&" feels almost like a beat, keepin' that CLI rhythm goin'

[Erik Trybom]

ls -d */

It displays the directories contained in the current directory. Not that obvious and very useful.

[spupy]

It's not installed by default, but

sl

Try it also with these args: -a -l

[NightwishFan]

I am famous for mentioning this one.

espeak "what you wanna say"