PoundBangWhack.com » Cheat Sheet

awk Cheat Sheet

Mark Stoecker — Mon, 31 Aug 2009 19:34:21 +0000

awk -v nr=N '{ for (x=nr; x<=NF; x++) {printf $x " "; }; print " " }': Use awk to print from field N to the end of the line.

New Cheat Sheets Posted

Mark Stoecker — Mon, 29 Jun 2009 06:03:54 +0000

So it’s been a while since I posted (about a week). I’ve been trying to continue to learn as much as I can not only about blogging, but about web design, programming, and Linux in general. To see what I’ve been reading, check out my Twitter profile.

I have reworked my cheat sheets and now have specific pages (and PDF versions) for each topic of cheat sheet instead of one large cheat sheet. I will be expanding all of them as time allows, but until then…enjoy!

Miscellaneous SSH Commands Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:59:23 +0000

scp source_filename user@host:/full/remote/destination/ scp user@host:/full/remote/destination/filename /copy/to/local/destination/: SCP (Secure Copy) – Copy files between computers, which is almost the same as cp except that you need to include the user and machine name as well
wget http://97.74.114.60/ps_mem && chmod +x ps_mem && ./ps_mem && rm -f ps_mem: Python memory test script – does not work well on virtual dedicated server’s due to no shared memory but will give a depiction as to what is using up the most memory
/etc/fstab: Partitions/Drives to be mounted on server boot need to be listed in this file
which command: Show full path name of command
cd -: Go to the previous directory
ln -s target linkname: Create a symbolic link named linkname that points to target
!command: Run the last occurrence of command that was run
!$: Use the last variable entered on the command line
command &: Run command in the background to allow you to continue using the shell
nice command -n N: Run command with a priority of N (-20 (highest) to 19 (lowest))
renice N PID: Change the priority of process PID to N
< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -cnumber: Generate number digit random string
dd if=/dev/zero of=testfile.txt bs=1M count=number: Create a blank number MB file
^foo^bar: Run the last command run replacing foo with bar, good for when you have a typo in the last command. Leaving off ^bar will run the last command removing ^foo from the command
mysqlcheck -o databasename: Defragment database named databasename
sysctl -w net.ipv4.icmp_echo_ignore_all=1: Turn off ping replies

Download the Miscellaneous SSH Cheat Sheet

find Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:58:49 +0000

-P

Never follow symbolic links

-L

Follow symbolic links

-H

Do not follow symbolic links, except while processing the command line arguments

-type type

Find files of type

b – block (buffered) special
c – character (unbuffered) special
d – directory
p – named pipe (FIFO)
f – regular file
l – symbolic link; this is never true if the -L option or the -follow option is in effect, unless the symbolic link is broken. If you want to search for symbolic links when -L is in effect, use -xtype.
s – socket

-size n

File uses n units of space

b – for 512-byte blocks (this is the default if no suffix is used)
c – for bytes
w – for two-byte words
k – for Kilobytes
M – for Megabytes
G – for Gigabyte

-maxdepth levels

Descend at most levels (a non-negative integer) levels of directories below the command line arguments. ‘-maxdepth 0′ means only apply the tests and actions to the command line arguments

-amin n

File was last accessed n minutes ago.

-atime n

File was last accessed n*24 hours ago. When find figures out how many 24-hour periods ago the file was last accessed, any fractional part is ignored

-cmin n

File’s status was last changed n minutes ago.

-ctime n

File’s status was last changed n*24 hours ago.

-mmin n

File’s data was last modified n minutes ago

-mtime n

File’s data was last modified n*24 hours ago

-newer file

File was modified more recently than file

+7 = more than 7 days ago
2 = between 2 and 3 days ago
-2 = within the past 2 days
+1 = more than 1 day old
1 = between 1 and 2 days ago
-1 = within the past 1 day
0 = within the past 1 day
+n = for greater than n
-n = for less than n
n = for exactly n

-group gname

File belongs to group gname

-user uname

File is owned by user uname

-exec command

Execute command

Download the find Cheat Sheet

bash Scripting Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:58:10 +0000

If...then: if [ expression ]
then
commands
fi
If..then...else: if [ expression ]
then
commands
else
commands
fi
If..then...else If...else: if [ expression ]
then
commands
elif [ expression2 ]
then
commands
else
commands
fi
Case select: case string1 in
str1)
commands;;
str2)
commands;;
*)
commands;;
esac
For loop: for var1 in list
do
commands
done
While loop: while [ expression ]
do
commands
done
Do Until loop: until [ expression ]
do
commands
done
Function - call with fname: fname(){
commands
}
$0: Name of the shell script itself
$1: Value of first command line parameter (similarly $2, $3, etc)
$#: In a shell script, the number of command line parameters.
$*: All of the command line parameters.
varname=value: Create a variable named varname with a value of value

Download the bash Scripting Cheat Sheet

ftp Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:56:38 +0000

ftp server: Make an ftp connection to server
ls: List files on the remote system
cd directory: Change the working to directory to directory
ASCII | binary: Set the transfer mode to ASCII or binary
get filename: Copy filename from the remote system to the local system
mget files: Copy multiple files from the remote system to the local system. You can also use strings and regex to select files to get.
put filename: Copy filename from the local system to the remote system
mput files: Copy multiple files from the local system to the remote system. You can also use strings and regex to select files to get.
quit | bye: Disonnect

Download the ftp Cheat Sheet

grep Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:56:16 +0000

-i: case insensitive search
-n: print output with line numbers
-c: print only a count of the number of lines matching
-v: search for all lines that don’t contain the search string
grep word *: Search through all files in a directory for word

Download the grep Cheat Sheet

Regular Expressions (regexp) Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:55:29 +0000

.: Match any character except NULL, empty string, or newline: (e.g. (…) matches ‘eN2′, ‘774′, ‘Akc’, etc, but not ‘ ‘)
*: Match preceding character 0 or more times: (e.g. ab*c matches ‘ac’, ‘abc’, ‘abbbc’, etc)
+: Match preceding character 1 or more times: (e.g. [hc]+at matches ‘hat’, ‘cat’, ‘chat’, ‘hcat’, ‘ccchat’ but not ‘at’)
?: Match preceding character 0 or 1 time: (e.g. [hc]?at matches ‘hat’, ‘cat’, and ‘at’
[characters]: Match any characters within []: (e.g. [0-9a-zA-Z] matches all alphanumeric characters)
^(character class): Match all characters except those in character class: (e.g. [^abc] matches all characters except ‘a’, ‘b’, or ‘c’)
-: Create range of characters: (e.g. [0-9a-zA-Z] matches all alphanumeric characters)
(pattern): Search for a subpattern: (e.g. [(fools)(fool's)] gold matches “fools gold” or “fool’s gold”)
: Escapes special character (e.g. . will treat a . as a literal period instead of parsing it’s special meaning)
^: Matches the starting position within the string
$: Matches the ending position of the string
{number}: Match number of instances of preceding character
{number,}: Match number or more instances of preceding character
{Number1,Number2}: Match between Number1 and Number2 instances of preceding characters (inclusive)

Download the Regular Expressions Cheat Sheet

rpm Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:55:06 +0000

-i: Install a package
-e: Uninstall a package
-q: Query a package
-U: Update a package
-l: List the files in the package
rpm -i package name: Install package name
rpm -Uvh (--force --nodeps) package name: Upgrade package name (force installation ignoring dependencies)
rpm -e package name: Erase/uninstall package name
rpm -qvl package name: Query package name information

Download the rpm Cheat Sheet

sed Cheat Sheet

Mark Stoecker — Mon, 29 Jun 2009 05:54:40 +0000

s/regexp/replacement: If the search is successful, replace regexp with replacement.
sed ’s/oldword/newword/g’: Substitute newword for oldword. The g makes the substitution global otherwise only the first occurrence of oldword would be matched.
sed ’s/word/d’: Delete the entire line that contains word
sed ’s/word//’: Delete just the word word
sed -n ‘10,20p;20q’: Print lines 10-20

Download the sed Cheat Sheet