Regular commands I use every day in Linux plus a few eclectic ones. Basically geared to the new user. Tips or thoughts, please let me know.
In Linux there is a manual for just about anything. Learn about almost everything by “man command” in the terminal. (e.g. man ls). Or type “command –help” for a basic description. Also, many man pages also cover configuration files (man resolv.conf).
Directories
cd ( change directory )
pwd ( print working directory )
mkdir ( mkdir )
- A name followed by a / means it’s a directory, bash is pretty good about figuring out what you mean if don’t use it but some apps don’t. A safe syntax would be
Command Output to Text (Standard Output)
ls /usr/bin > /home/user/Desktop/programs.txt
Add to an existing text file:
ls /sbin >> /home/user/Desktop/programs.txt
Pipes ( | )
- Useful for using programs in conjunction with others
ls -l | less
Filters
Popular filters used after piping.
sortuniq - removes duplicate lines of datagrep - returns the output of a specified pattern of charactershead, tail - outputs the first of last lines of outputtr - translates characters - can be used for upper/lower case conversion
Use grep to extract patterns from files
grep EE /etc/X11/xorg.conf
ls -all /dev | grep dvd
glxinfo | grep -i direct
Files and File Permissions
View file permissions
- List the files in long view:
ls -l
-rwxr--r-- 1 user user 225444 2007-05-01 21:58 abc.pdf
| | | | | |
| | | world | group name
| | group owner name
| owner/user
directory?
r = read = 4
w = write = 2
x = executable = 1
Change File Permissions
owner = 4+2+1 = 7 , group = 4 …
The above file’s permissions numerically is 744 to change permissions of the above file:
chmod 755 abc.pdf
Change Ownership
chown user:group /home/user/document.txt
Lazy way of make a file executable 
chmod +x /usr/bin/gmailto
File Systems
Show all partitions and their types (may not work on all types)
sudo fdisk -l
Show partition used/available space:
df -h
See all file systems mounted:
cat /proc/mounts
Sort Directories by How much space they consume
du | sort -nr
Mount a Volume and add it in permanently:
- The fstab file tells system of available disks/partitions and can automatically mount it at boot.
sudo mkdir /mnt/USB-Drive
sudo mount /dev/sda2 -t vfat -o rw /mnt/USB-Drive
- types include hfsplus, vfat…
Enter in /etc/fstab:
/dev/sda2 /mnt/OSX hfsplus ro,exec,auto,users 0 0
/dev/sda4 /mnt/Shared_Disk vfat users,auto,uid=1000,gid=100,umask=007 0 0
- ro - read-only, rw - read-write, auto mounts filesystem on boot
Unmount all possible file systems:
umount -a
Check File Systems
- Mounted file systems should be checked from the Installer CD/DVD or on boot.
Force file system check on next boot (won’t do it immediately):
sudo touch /forcefsck
Reboot immediately and check for errors:
sudo shutdown -Fr now
Change how often fsck runs at boot:
sudo tune2fs -c 30 /dev/hda
Check and mark bad blocks on damaged drives:
mke2fs -j -c /dev/hda3
Get UUID of devices:
At times the fstab file will require a device ID (UUID) be supplied.
ls /dev/disk/by-uuid -alh
Swap
Create swapfile
dd if=/dev/zero of=/swapfile bs=1024 count=2097152
- Swap is recommended to be 1-1/2 to 2x the value of the RAM to use for hibernation.
- 1 GB = 1024 MB = 1024 x 1024 kB = 1048576 kB = 1048576 kB x 1024 bytes/kB = 1,073,741,800 bytes10
mkswap /swapfile
swapon /swapfile
Add to /etc/fstab:
/swapfile swap swap defaults
Controlling Swap
Turn off swap:
swapoff -a /swap
- Swapiness is the input/output priority of swap. To measure the current value:
cat /proc/sys/vm/swappiness
To change the swap priority (higher value means more swapping):
sysctl vm.swappiness=10
- values of 20 or lower are better for laptops.
File Compression
Pack:
tar gunzip:
tar cvpzf /AreaToSaveTo/yourcompressedfile.tgz –exclude=/this/folderorfile /CompressionStarts/Here
tar.bz2(tbz2) (block sorted, better compression):
tar -cvjf files.tar.bz2 fileorfolder
bzcat linux-2.6.XX.tar.bz2 | tar x
Unpack:
tar gunzip:
tar -xf file.tgz
tar xvjpf file.bz2 /startplace
tar.bz2(.tbz2):
bzcat file.tbz2 | tar file.tar
View contents of tar files:
tar tzvf name_of_file.tar.gz | less
unrar
unrar e file.part01.rar
- Now works in conjunction with file roller.
Span Multiple Volumes
create:
tar -c -M --tape-length=2294900 --file=part1.tar too-large-archive.tgz
extract:
tar -x -M --file=part1.tar too-large-archive.tgz
- At prompt specify new (n),
- then specify volume name (e.g. n part2.tar)
- tape-length is 1024 bytes measurement
Or use “split” to break a large volume:split -b 2m largefile LF_
- 2m = 2 megabytes LF is the prefix for new name
tar -cvj /full/path/to/mybigfile | split -b 650m
Put back together:
cat file* > newfile
Backup and Restore
Tar - From Install CD
cd /mnt/gentoo
tar -czpvf /mnt/gentoo/MacBook-Gentoo-Backup.tgz *
Rsync - Full Backup
rsync -avtp --delete --exclude=/home/user/somedir /source/dir /destination/dir
- -a archive, -v verbose
- -t preserve modification times, -p permissions
- –delete removes destination file if has been removed from source
- –links recreate symlinks
- -z compress from source to destination - good for slow connections.
- use “-a e ssh source name@hostname:dest” for ssh
Rsync - Incremental Backup
NEEDED? I think the above does Incremental too.rsync -b –backup-dir= combination
- used for daily or every other day
Users
Add user
useradd -m -G adm,audio,cdrom,cdrw,cron,games,plugdev,portage,shutdown,usb,users,video,wheel -s /bin/bash user
- Groups may vary some per distribution, this one is for Gentoo.
- Some groups may not be available until installation is finished
Add/delete user to group
gpasswd -a user plugdev
gpasswd -d user plugdev
See what groups user belongs to
id
Remove user
userdel username
CD / DVD
Writing to CD/DVD with Rock-Ridge support
- Rock-ridge support add Unix file extensions and attributes for iso9660 standard disks.
- DVD are marked as 4.7GB capacity but thats just the marketing measure. In terms the computer understand the space on a DVD is 4.368 GB’s
- 1 GB = 1048576 kB x 1024 bytes/kB
- DVD +R at 4x or 8x for best performance
DVD
growisofs -Z /dev/dvd -lrJ -joliet-long /path/to/files
- -Z means to start at the beginning of the dvd
- -l allows long filenames (breaks DOS compatability)
- -r Rock-ridge support
- -J Add Joiliet support
- -joliet-long - allows Joliet filenames to be 103 characters long instead of 64 - breaks joliet compatibility but works in most cases.
CD
mkisofs -o my.iso -lrJ /path/to/files
- Then burn iso to CD.
- Not sure if I can write directly to CD, from what I’ve seen it would seem that I can’t.
Blanking a Disk
- If you want to blank a disk or it already has a file-system on it you’ll see an error like “WARNING: /dev/hda already carries isofs!” then reinitialize the filesystem:
DVD
dvd+rw-format -f /dev/dvd
growisofs -Z /dev/hda=/dev/zero
CD
cdrecord -v dev=/dev/hda blank=fast
cdrecord -v dev=/dev/hda speed=2 blank=fast
cdrecord -vv dev=1,0 blank=all
ISO
Write ISO to CD/Drive:
dd if=name.iso of=/dev/sdb1
Mount ISO:
mount -t iso9660 -o loop,ro name.iso /mnt/cdrom/
mount /path/to/name.iso /mnt/cdrom -t iso9660 -o ro,loop=/dev/loop0
Create an ISO from a DVD or CD:
dd if=/dev/hda of=name.iso
Create and ISO from a file/directory:
mkisofs -o name.iso /path/to/file_or_directory
CDRWin (.bin/.cue) images to .iso:
bchunk name.bin name.cue name.iso
bin2iso name.cue
Converting CloneCD images to ISO:
ccd2iso name.img name.iso
Converting nrg (Nero) images to ISO:
nrg2iso name.nrg name.iso
Support for writting large file sizes
- ISO has file size limit of 4GB
- untested - udf support is still in alpha
mkisofs -o my.iso -lrJ -allow-limited-size -udf file-or-pathtofiles
growisofo -Z /dev/dvd -lrJ -allow-limited-size -udf file-or-pathtofiles
Mouse/Keyboard
Change keymaps:
setxkbmap dvorak
Map pointer buttons to keyboard:
xmodmap -e 'keycode 116 = Pointer_Button2'
xmodmap -e 'keycode 108 = Pointer_Button3'
xkbset exp m
Hardware Info
Kernel messages about hardware
dmesg | less
Cpu info:
cat /proc/cpuinfo
List all PCI devices
lspci
Detect hardware as it’s plugged in
tail -f /var/log/messages
For more detail
lshal --monitor
Icons / Cursors / Fonts …
Reset Icon Cache
gtk-update-icon-cache -f /usr/share/icons/hicolor/
Convert Windows Icons to Linux
Reset cache for fonts:
fc-cache -vf
Build font info per directory:
mkfontscale
mkfontdir
Replace fonts script
cd /etc/fonts/conf.d/ && ln -sf ../conf.avail/61-replace-corefonts.
Take screenshot of selected area
import filename.png
Set gamma
- If you have ability to calibrate your own icc profile ( Macintosh’s do ) copy the icc profile to Linux and use “xcalib icc.profile”, otherwise a basic gamma can be set:
xgamma -bgamma 0.925 -ggamma 0.925 -rgamma 0.925
System
Shutdown at a specific time
shutdown -h 22:33
Manually Shutdown
shutdown -P now
date
use “date” to check date and to set system clock:
date MonthDayHourMinuteYear
Find out kernel version:
uname -r
Start Program that isn’t in the Systems Path
- Only programs that are in a system’s PATH setting can be started by typing the command
./program
Disable Touchpad whilest Typing
syndaemon -d -t -i 2
Networking
Samba
Change or add password to smbconf:
sudo smbpasswd -L -a user
Mount SMB share to folder
sudo smbmount //192.168.1.105/user/ mnt/directory -o username=username,password=pass,uid=1000,mask=000
Mount all Samba Shares in fstab
mount -a -t smbfs
SSH / SCP
Remote login with ssh with username (diiferent that the one you’re using)
ssh -l username 192.168.1.101
Copy remote file to local file
scp -p user@192.168.1.101:~/Desktop/file.name file.name
Download entire website:
wget -r http://www.robot-frog.com/
Advanced
Bash
The ~/.bashrc file
- Adding PATHs to the ~/.bashrc file will make the system aware of another folder that has executables.
- Shortcuts can be created for common commands
export PATH=$PATH:/home/user/.scripts
alias capscreen="import ~/Desktop/screen.png"
Analyze Bash History
cat .bash_history | tr '|' '\n' | awk '{print $1}' | \
egrep -o '([^/]+)$’ | sort | uniq -c | sort -nr | awk ‘{print $2 “,” $1}’ To see the preset variables already defined for bash:
set
Search History
ctrl-r
Cron
- Cron is the system timer. It checks every minute for commands to run.
To edit a crontab (cron jobs)
crontab -e
# minute (0-59),
# | hour (0-23),
# | | day of the month (1-31),
# | | | month of the year (1-12),
# | | | | day of the week (0-6 with 0=Sunday).
# | | | | | user
# | | | | | | commands
43 08 * * * env DISPLAY=:0.0 audacious [[/home/user]] /My\ Music/Other/Alarms/301gq.mp3
chroot - (changing root)
- Userful for logging into your current Linux from an installtion CD
su
mkdir /mnt/osname
mount /dev/sda3 /mnt/osname
mount -t proc none /mnt/osname/proc
mount -o bind /dev /mnt/osname/dev
chroot /mnt/osname /bin/bash
Compile Kernel
make oldconfig
make menuconfig
make clean zImage modules modules_install install
For PPC “make pmac32_defconfig” will generate a basic config.
Find Modules
find /lib/modules/2.6.20-gentoo-r2-ibook-SE-g3 -type f -iname ‘*.o’ -or -iname ‘*.ko’
Add the screen program to be able to background a terminal process
screen command
- CTRL + A + D to background it, to return it:screen -r
Use noup to continue a process even if you log out
noup command
Unsorted / Less Used
sudo echo >> no work
echo "my text" | tee /etc/portage/package.use
See whats taking up ram:
ps auxf --sort size
Generate Modelines for xorg.conf
gtf screenwidth screenheight vertrefresh
Reset settings in gconf:
gconftool-2 --recursive-unset /apps/compiz
GDM conf file
Touch Entire System
(careful I’ve done this before when my files got dated wrong from a dead battery. But I tried again and the files are put where the command is executed - all 0 bytes)
find /| xargs touch - m
Allow window executables to run directly (will need Wine and misc. binaries enabled in kernel)
In /etc/sysctl.conf add
fs.binfmt_misc.register = :WINEXE:M::MZ::/usr/bin/cedega:
and add to fstab
none /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0
Re-size Images
convert writes new image, mogrify overwritesconvert image.jpg --resize 800x600 newresized.pngmogrify -geometry 1024x768 *.png
Copy ALL Files (+invisible, hard links, softlinks)
find . -depth -print0 | cpio –null –sparse -pvd /mnt/newhome/
Create random numbers, hex letters
dd if=/dev/random bs=1 count=5 2>/dev/null | xxd -ps
Run programs sequentially or concurrently
program && program
program & program
Hardware acceleration enabled?
glxinfo | grep rendering
A simple web server
Share files in directory and all subfolders:
python -c "import SimpleHTTPServer;SimpleHTTPServer.test()"
View in:
http://localhost:8000 or http://your_ip:8000/
Debian Specific:
Run Program as normal user:
sudo dpkg-statoverride --update --add root root 4755 /usr/share/app
drive space show taken by installed packages
dpkg-query -W --showformat='${Installed-Size;10}\t${Package}\n' | sort -k1,1n Rebuild Font Directory
dpkg-reconfigure fontconfig
