Jim Kerr - Alaska Juggler

 Why is it so hard to understand simplicity?





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"Unix is very simple, but it takes a genius to understand the simplicity."
(Dennis Ritchie)
OpenBSD Tricks:

Aliases to paste into your bashrc
mf ="mount -t msdos /dev/fd0Ba /floppy"  # This will mount a MSDOS formatted diskette
mcd="mount /dev/cd0a /cdrom" # Mount CDROM Drive
musb="mount /dev/sd0i /thumb
netstat -I sis0 -w 5
This gives the network I/O status of a netgear card interface (-I) (sis0) every 5 seconds (-w)

ps -aux
(Process Started listing)
Setup tricks
etc/sysctrl.conf file
make sure the ddb.panic = 0 # Set a machine's default to reboot after a kernel panic
net.inet.ip.forwarding =1 # set ip forwarding on for bridging and packet filtering
/etc/rc.conf.local - Turn on the Packet Filter program if you have set it up
pf = yes
stopping pf
pfctl -d
starting pf
pfctl -e
starting pf with configuration file
pfctl -f /etc/pf.conf
More PF commands
# pfctl -f /etc/pf.conf Load the pf.conf file
# pfctl -nf /etc/pf.conf Parse the file, but don't load it
# pfctl -Nf /etc/pf.conf Load only the NAT rules from the file
# pfctl -Rf /etc/pf.conf Load only the filter rules from the file
# pfctl -sn Show the current NAT rules
# pfctl -sr Show the current filter rules
# pfctl -ss Show the current state table
# pfctl -si Show filter stats and counters
# pfctl -sa Show EVERYTHING it can show
Mount a floppy disk
mkdir /floppy    #The first time you mount a floppy disk you need to create a mount point:
ls /dev/fd*          # to find a floppy device
mount -t msdos /dev/fd0Ba /floppy        # This will mount a MSDOS formatted diskette
cd /floppy        # Change into the floppy directory
cd /                  # Change to the root directory so the diskette can be unmounted
umount /floppy            # unmount the floppy diskette

tar -zxvf bash*.tgz /
will untar a comppressed tarball into the current directory
Mount a CD-ROM (at /cdrom mount point)
after creating the a mount point (i.e.mkdir /cdrom)
mount /dev/cd0a /cdrom
Disk Usage
df usage of major partitions
du -s size of current directory
ls -la full info. file listing incl. hidden files
ls -laF full info. file listing incl. hidden files & file types
#where @ is link, * executable, / is directory
ls -ld full info. directory listing
ls -laF | sort | grep "/" #list all directories
ls -laF | sort | grep "*" #list all executables
Data and File tricks
sed 's/^0/string/g' file-in.txt>file-out.txt
globally replaces zero at the beggining of the line with string and write the output to file-out.txt - don't forget the quotation marks.
find ./ -type f | xargs grep -l 'http://AlaskaEconomy.uaa.alaska.edu' \
| xargs sed -a '' -e 's/http://AlaskaEconomy.uaa.alaska.edu/Living Conditions/g'
4.41. How do I make substitutions in every file in a directory, or in a complete directory tree?
4.41.1. - ssed and Perl solution
The best solution for multiple files in a single directory is to use ssed or gsed v4.0 or higher:
sed -i.BAK 's|foo|bar|g' files # -i does in-place replacement
If you don't have ssed, there is a similar solution in Perl. (Yes, we know this is a FAQ file for sed, not perl, but perl is more common than ssed for many users.)
perl -pi.bak -e 's|foo|bar|g' files # or
perl -pi.bak -e 's|foo|bar|g' `find /pathname -name "filespec"`
For each file in the filelist, sed (or Perl) renames the source file to "filename.bak"; the modified file gets the original filename. Remove '.bak' if you don't need backup copies. (Note the use of "s|||" instead of "s///" here, and in the scripts below. The vertical bars in the 's' command let you replace '/some/path' with '/another/path', accommodating slashes in the LHS and RHS.)
To recurse directories in Unix or GNU/Linux:
# We use xargs to prevent passing too many filenames to sed, but
# this command will fail if filenames contain spaces or newlines.
find /my/path -name '*.ht' -print | xargs sed -i.BAK 's|foo|bar|g'
Perl global string/file replace
$ perl -pi -e 's/string1/string2/g' *
Getting rid of those pesky ^Ms that windows notepad leaves:
replace the ^M with tr

tr -d "\015" < dosformatted.txt > unixformatted.txt
Globally replace text in many files in place
find -name Root | xargs perl -pi -e 's/Old Text/New Text /g'
Just in case you need the ascii code here is an ASCII Table for you
$ find / \! -name '*.c' -print
Print out a list of all the files whose names do not end in ``.c''.

$ find / \! \( -newer ttt -user wnj \) -print
!Print out a list of all the files which are not both newer than``ttt'' and owned by ``wnj''.
$ find / \( -newer ttt -or -user wnj \) -print
!Print out a list of all the files that are either owned by ``wnj'' or newer than ``ttt''.
$ find / \! -fstype local -prune -or -name '*.core' -print
!Print out a list of all core files on local file systems.
dd if=floppy34.fs of=/dev/rfd0c bs=32k
!Write an OpenBSD floppy image to a floppy disk.
eject /dev/rcd0c
Eject the first CD device. This will work even if there is no CD in the drive.
Here is a handy backup routine to copy only files that have changed since the last backup:
rsync -r -u -v /Stuff/* /Volumes/Backup/Stuff
rsync -r -u -v /Users/WhatsYourFace/* /Volumes/Backup/WhatsYourFace
cat /proc/cpuinfo #for CPU information
cat /proc/meminfo # for memeory information
cat > filename.txt # then type or paste info to capture text and end with contol-d
tar -xvf tarfile.tar # unpack most archives
mkdir /cdrom # makes a directory to mount cdroms
mount /dev/cdrom /cdrom #mounts a cdrom in the /cdrom directory created in the last line

–A notice the capital “-A” for all processes
stty rows 46 cols 100
Start Xwindows with:
find ./ -name filename
cd ~ [go to home directory
find ./ -name lost.file*
ls –laF

Sort a directory via a pipe:
ls -l | sort -n +1
ls = list directory -l = use long format
| = pipe output into the next command
sort -n +1 = sort using -n (numbers as opposed to letters) on the +1 (second field)
while in the sbin directory you can add users with the following:
./adduser –c “ftp guest” -d /home/iserguest -p secretpassword
Password change - Go to Single User Mode via hard boot (turn off computer or reset it)
Go to the boot prompt and type: linux single
Conversion tricks
EOL characters:
Macintosh: CR
Unix: LF

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