Glossary What are the different logins (e.g. interactive login) Code Snippets (a.k.a Unix commands that I always seem to forget....) Repeating words from the current command Unzipping a ~tar.gz file Download and unzip in one command Using mail to send something from a script doing something on each line of a file How to over-ride an alias Listing directories in a file Print out path elements one per line Find examples Helpful ls switches Stop a job from running if it's already running Debugging a shell script Base conversion with shell arithmetic Grep Deal with CTRL and ^M problems Setting default values for variables System activity reporter rysnc disk usage curl Useful Switches Examples Screen Documentation Some Commands Files Convert encoding on files Logging Log to either a file or stdout Port Fun Find out what's listening on a port To see all the ports open for listening upon the current host you can use another command netstat Info Find symlinks in directories fstab fun To basically reload your fstab, run: To get uuid for a volumne:

Glossary

What are the different logins (e.g. interactive login)

An interactive login shell is one where you authenticate to the system, load the shell, and run commands manually from the shell prompt. ssh some.server.com gives you an interactive login shell, as does logging in via the console.

 

A non-interactive login shell is one where you authenticate to the system, load the shell, and run a specific series of commands automatically, after which the shell terminates. ssh some.server.com 'ls -l' gives you a non-interactive login shell.

 

An interactive non-login shell is what you get when you open a terminal window in X (like Konsole, xterm, eterm, etc). You're already authenticated so you don't have to put in a username and password again, but you get a prompt where you can manually type in commands.

 

A non-interactive, non-login shell is what you get when you run shell scripts. You don't get a prompt, you don't have to enter a username or password, but a shell runs for you.

 

Code Snippets (a.k.a Unix commands that I always seem to forget....)

 

Repeating words from the current command

All arguments:

 

First argument:

 

Last argument

 

Argument n

 

 

Unzipping a ~tar.gz file

 

Download and unzip in one command

 

Using mail to send something from a script

 

doing something on each line of a file

 

How to over-ride an alias

For example, if you have alias rm=rm -i, you can override

the alias instruction use a \ before, ie

\rm will call the real rm not the alias.

 

Listing directories in a file

 

Print out path elements one per line

 

Find examples

Find UNIX files modified within a number of days

To find all files modified within the last 5 days:

The - in front of the 5 modifies the meaning of the time as "less than five days." The command

displays files modified more than five days ago. Without the + or -, the command would find files with a modification time of five days ago, not less or more.

 

Find files and remove them

 

Find files matching a pattern using OR

 

Find files that are not in a certain directory

or

 

Helpful ls switches

For more info http://www.mkssoftware.com/docs/man1/ls.1.asp

Sort by create date

Display sizes in an easier format

Display permissions, links, owner, group, size, time, name

List all entries including those starting with a period (.)

 

 

Stop a job from running if it's already running

 

Debugging a shell script

Turn on shell tracing with:

For example:

 

Base conversion with shell arithmetic

 

Say you have some number but, in your script, you need to work on it in another base. Automating this conversion is done easily with shell arithmetic. One way is to use shell arithmetic to convert a number from a given base to decimal. If a number is given in an arithmetic expansion, it's assumed to be in decimal notation unless it's prefaced by a either a zero -- in which case it's assumed to be in octal -- or 0x -- in which case it's assumed to be in hexadecimal. Type the following to get decimal output for some octal and hex values:

 

You can also specify any arbitrary base between 2 and 64 with the following format:

 

Try converting numbers in binary, octal, hex, and other bases to decimal by typing the lines shown below.

 

 

 

Grep

Match words

The \< and \> enclosures are useful pattern builders: They enclose a whole word to be matched -- they won't match an enclosed pattern unless that pattern is a word of its own. A word is defined as any number of word-forming characters (numbers, letters, and the underscore characters) that are delineated by a nonword character on both sides. Nonword characters include any of the following:

 

• The beginning of the line
• A whitespace character
• A punctuation character
• The end of the line
• Any other character excluding letters, numbers, or the underscore

 

These enclosures can be a great timesaver, but they're often underutilized -- probably because not every regexp implementation supports them. If yours does, get in the habit of using them.

 

Enclose a word to match that word alone, like so:

 

 

The regexp in this example won't match the word ecosystem, systemic, or system/70, nor will it match lines where the pattern system appears just anywhere on the line -- it will only match those lines where system exists as a word of its own.

 

Combine the enclosures with groupings in parentheses to match parts of words.

 

To match lines containing words that begin with pre, use:

 

 

The preceding example matches lines containing the words preface and preposterous, but not spread or Dupre.

From Hone your regexp pattern-building skills

 

Deal with CTRL and ^M problems

 

 

Setting default values for variables

 

 

This means: if the variable "Host" is

not already set, execute the command

"uname -n" and set the variable to

the returned value.

 

System activity reporter

man page

 

 

You can get memory stats

 

Swap stats

 

and socket

 

Other useful command is

 

rysnc

sudo rsync -vaxE --delete --ignore-errors / /backup

 

disk usage

find total usage for directories

 

curl

Useful Switches

-o/--output

Write output to instead of stdout. If you are using {} or [] to fetch multiple documents, you can use '#' followed by a number in the specifier. That variable will be replaced with the cur rent string for the URL being fetched.

Like in:curl http://{one,two}.site.com -o "file_#1.txt"

or use several variables like:curl http://{site,host}.host1-5.com -o "#1_#2"

You may use this option as many times as you have number of URLs.

See also the --create-dirs option to create the local directories dynamically.

 

-i/--include

(HTTP) Include the HTTP-header in the output. The HTTP-header includes things

the document, HTTP-version and more...

 

If this option is used twice, the second will again disable header include.

 

-I/--head

(HTTP/FTP/FILE) Fetch the HTTP-header only! HTTP-servers feature

the command HEAD which this uses to get nothing but the header

of a document. When used on a FTP or FILE file, curl displays

the file size and last modification time only.

 

If this option is used twice, the second will again disable

header only.

 

-L/--location

(HTTP/HTTPS) If the server reports that the requested page has a

different location (indicated with the header line Location:)

this flag will let curl attempt to reattempt the get on the new

place. If used together with -i/--include or -I/--head, headers

from all requested pages will be shown. If authentication is

used, curl will only send its credentials to the initial host,

so if a redirect takes curl to a different host, it won't intercept

the user+password. See also --location-trusted on how to

change this.

 

If this option is used twice, the second will again disable

location following.

 

 

 

Examples

Sending an XML Post Request

 

Screen

Documentation

http://www.hmug.org/man/1/screen.php

 

Some Commands

 

Files

Convert encoding on files

For example, ISO-8859-1 to UTF-8

 

Logging

Log to either a file or stdout

This might not be the best way but it works. By passing in an argument in the first position, it'll log the echo to stdout

 

 

Port Fun

Find out what's listening on a port

To see all the ports open for listening upon the current host you can use another command netstat

 

Info

 

Find symlinks in directories

 

fstab fun

To basically reload your fstab, run:

 

To get uuid for a volumne: