2. RMDIR – removes a directory only if it is empty
RMDIR –r – removes a directory regardless if it is
empty or not
CHMOD 777 –r /user/dan – recursively changes the
permissions of the directory /user/dan to
RWXRWXRWX
grep – pattern matching for example ps –ef |grep
apache2 will look for all processes running under the
name apache2
egrep – used in regular expressions
3. find – find the location of a file (or files) on a hard
drive at the command line
echo – writes data to the screen (standard output)
The TTY – Screen is always standard output (STDOUT)
more – displays the contents of a file one page at a time
(hard for long files like syslog)
clear – clears the screen of text and provides the
command prompt
chown – change the owner of a file or directory
rm – remove a file
4. mv – move a file to a new place and or new name
chgrp – change the group ownership of a file
mkdir – make a directory
ls – list the files in a directory, ls –la show the long
form (including permissions and owners) of the files
in a directory
cat – an alternative to showing the data in a file all at
once
pwd – display the current directory
passwd – change the password of the currently logged
in user
5. >> - append data to the END of a file
> - overwrites the file and any data in it
| - pipe character – strings commands together
|| - logical OR – in that A || B in a loop, condition A or
condition B
& - executes your process in the background – so you can
still use the command line ./script.sh & will run your
process in the background
&& - Logical AND A && B if A succeeds, run B
sleep – stop execution of the script for a specified number
of seconds sleep 20 means sleep for 20 seconds
6. diff – compares two files (this is great for seeing what
changes were made in a script against the original and
modified)
sdiff – only works with the 132 character display, but
compares files side by side
lp – prints a file to the configured printer
lpstat – shows the user what is in the printer queue
( ) – runs the enclosed command in a sub-shell
(( )) – evaluates and assigns a value to a variable and
does math in a sub-shell
7. $(( )) – evaluates the enclosed expression
[ ] – test an expression to see if it is true or false
< > - used to compare values or strings
$( ) – command substitution – great when doing
logical OR’s or AND’s
8. ++ - auto increment a value for I=1 ++ (takes I up by 1
for every loop)
-- - auto decrement a value for I=100 -- (takes I down
by 1 for every loop)
<= - less than or equal to
>= - greater than or equal to
9. I will expect to see this in the header of every Unix Script
you will turn in:
#!/bin/sh (tells the computer to use a bourne shell)
#
# Script: Name of script (what you named this file)
# Author: Your Name (so I know who wrote it)
#Date: (the date you wrote it)
#Revision: 1.1.A(how many times it changed, and what
state it is in(A, B, D, T or P)
All scripts should also have A, B, D, T or P at the end of the
revision statement so I know if it is Alpha, Beta, Dev, Test, or
Production. All scripts turned in should be production scripts
10. How to get your script to do more useful stuff
If. Then
if [test]
Then
stuff I want the computer to do
fi
If. Then. Else
if [test]
Then
stuff I want the computer to do
Else
Stuff I want the computer to do if the first condition didn’t happen
fi
11. for
for A=1
do
stuff I want the computer to do
done
While
While A=1
do
stuff I want the computer to do
done
12. Until
until A=1
do
stuff I want the computer to do
done
Case
case A=1
stuff I want the computer to do
case A != 1
stuff I want the computer to do
easc