linux

I've been using debian since potato, now mainly use ubuntu.

I'm using awesome window manager now.

My setup is on github: usrjim/env

I've been a vim user for a long time, but now emacs is my primary editor.

sub pages

debian 6 squeeze

build mongodb extension for PHP under Debian 6 squeeze

$ apt-get install php5-dev build-essential php-pear
$ pecl install mongo

install / uninstall services

$ update-rc.d service-name defaults
$ update-rc.d -f service-name remove

basic commands

list one level dir by size

$ du -k --max-depth=1|sort -nr|more

resize image

$ convert original.jpg -resize 640x640 resized.jpg

find file in a folder

$ find -maxdepth x|grep 'name'

take screenshot

$ import screenshot.png

paste to terminal

$ shift-ins

get file full path

$ find `pwd` -name the_file

tar and ssh file

$ tar cf - dir | ssh remote_host "(cd dir2; tar xf -)"

playing the top command:

| h       | help                              |
|---------+-----------------------------------|
| f       | fields                            |
| V       | forest view                       |
| H       | threads                           |
| R       | sort                              |
|---------+-----------------------------------|
| i       | toggle idle task                  |
|---------+-----------------------------------|
| L       | locate string                     |
| &       | find again                        |
| > and < | move sort column                  |
|---------+-----------------------------------|
| x       | toggle highlight for sort field   |
| y       | toggle highlight for running task |
| z       | toggle color                      |
| B       | toggle bold                       |
|---------+-----------------------------------|
| A       | alternative display               |
| a       | move to next field group          |
| w       | move to previous field group      |
| g       | enter field group                 |
|---------+-----------------------------------|
| k       | kill a pid                        |

display non-idle with one frame: top -ibn 1

ps sort by cpu: ps aux –sort c

show memory usage in detail: pmap -x [pid]

lolcat: a colorful cat

about acl on ubuntu, FilePermissionsACLs, a quick note:

copy acl from one dir to another: getfacl dir1 | setfacl -b -n -M - dir2

Output from getfacl is accepted as input for setfacl when using -M, -b clear ACLs, -n do not recalculate effective rights mask, - read from stdin.

check permission recursively:

namei /path/to/file

to check permission on file/dir:

sudo -u user stat /path/to/dir/or/file

to check write permission:

sudo -u user test -w /path/to/dir/or/file; echo $?

or

sudo -u user test -w /path/to/dir/or/file && echo "ok" || echo "not ok"

check read and execute permission use -r and -x flags.

and for tmux, to highlight the active pane, can set both fg and bg color, which will show as a bold line for the active pane:

set-option -g pane-active-border-fg red
set-option -g pane-active-border-bg red

LVM

to test I created a 3G disk from virtualbox, and resize it to 1G.

create

$ fdisk -l
$ fdisk -c -u /dev/sdb

here:
n -> p -> 1
t -> 8e
p
w

$ pvs
$ pvcreate /dev/sdb1

$ vgs
$ vgcreate -s 32M sitedata /dev/sdb1

$ vgdisplay sitedata (get PE)
$ lvs
$ lvcreate -l 95 -n sitephotos sitedata

$ mkfs.ext4 /dev/sitedata/sitephotos
 
$ mount /dev/sitedata/sitephotos /opt/sitephotos

$ df -h

resize

$ umount /opt/sitephotos
$ e2fsck -ff /dev/sitedata/sitephotos
$ resize2fs /dev/sitedata/sitephotos 1G
$ lvreduce -L -2G /dev/sitedata/sitephotos
$ mount /dev/sitedata/sitephotos /opt/sitephotos

create from free space

$ vgdisplay sitedata (get PE)
$ lvcreate -l 64 -n sitedoc sitedata 
$ mount /dev/sitedata/sitedoc /opt/sitedoc
 
$ df -h

find modified files during an installation:

$ touch /tmp/afile
$ find /etc -newer /tmp/afile

can check accessed too:

$ find /etc -anewer /tmp/afile

to find between custom peroid:

$ touch -t 200712021345.00 /tmp/file1
$ touch -t 200712040130.00 /tmp/file2
$ find /etc -newer /tmp/file1 -a ! -newer /tmp/file2

bash

(note, on iTerm, set profile keys option to +Esc)

(from Bash Shortcuts For Maximum Productivity)

Command Editing Shortcuts

| Ctrl + a  | go to the start of the command line                                                                          |
| Ctrl + e  | go to the end of the command line                                                                            |
| Ctrl + k  | delete from cursor to the end of the command line                                                            |
| Ctrl + u  | delete from cursor to the start of the command line                                                          |
| Ctrl + w  | delete from cursor to start of word (i.e. delete backwards one word)                                         |
| Ctrl + y  | paste word or text that was cut using one of the deletion shortcuts (such as the one above) after the cursor |
| Ctrl + xx | move between start of command line and current cursor position (and back again)                              |
| Alt + b   | move backward one word (or go to start of word the cursor is currently on)                                   |
| Alt + f   | move forward one word (or go to end of word the cursor is currently on)                                      |
| Alt + d   | delete to end of word starting at cursor (whole word if cursor is at the beginning of word)                  |
| Alt + c   | capitalize to end of word starting at cursor (whole word if cursor is at the beginning of word)              |
| Alt + u   | make uppercase from cursor to end of word                                                                    |
| Alt + l   | make lowercase from cursor to end of word                                                                    |
| Alt + t   | swap current word with previous                                                                              |
| Ctrl + f  | move forward one character                                                                                   |
| Ctrl + b  | move backward one character                                                                                  |
| Ctrl + d  | delete character under the cursor                                                                            |
| Ctrl + h  | delete character before the cursor                                                                           |
| Ctrl + t  | swap character under cursor with the previous one                                                            |
| Ctrl + _  | undo                                                                                                         |

Command Recall Shortcuts

| Ctrl + r | search the history backwards                                             |
| Ctrl + g | escape from history searching mode                                       |
| Ctrl + p | previous command in history (i.e. walk back through the command history) |
| Ctrl + n | next command in history (i.e. walk forward through the command history)  |
| Alt + .  | use the last word of the previous command                                |

Command Control Shortcuts

| Ctrl + l | clear the screen                                                       |
| Ctrl + s | stops the output to the screen (for long running verbose command)      |
| Ctrl + q | allow output to the screen (if previously stopped using command above) |
| Ctrl + c | terminate the command                                                  |
| Ctrl + z | suspend/stop the command                                               |

Bash Bang (!) Commands

Bash also has some handy features that use the ! (bang) to allow you to do some funky stuff with bash commands.

| !!      | run last command                                                                                                                     |
| !blah   | run the most recent command that starts with ‘blah’ (e.g. !ls)                                                                       |
| !blah:p | print out the command that !blah would run (also adds it as the latest command in the command history)                               |
| !$      | the last word of the previous command (same as Alt + .)                                                                              |
| !$:p    | print out the word that !$ would substitute                                                                                          |
| !*      | the previous command except for the last word (e.g. if you type ‘find some_file.txt /‘, then !* would give you ‘find some_file.txt‘) |
| !*:p    | print out what !* would substitute                                                                                                   |
Search Blog: