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Command Line session 2

Submitted by Conceptor on Wed, 18/08/2004 - 12:12pm.

After finishing open topics and question from last session . session 2 will be started.

Redirection and Pipes
```
 $ ls -l >  /dev/pts/? ur current pts.
```
```
 $ ls -l >   / output 
```
```
 $ wc -l < output 
```
```
 $ ls -l / | wc -l > count 
```
```
 $ ls -l / | wc -l |tee /dev/tty9 > count_file 
```
When you get the result of this command ,you were notified that u shouldn't list ur username on every entry .
```
 $ ls -l /opt/new_apps > apps_list
```
the comman way is using sed stream editor.
```
 $ sed 's/root/  /' apps_list
```
once again some of your friends tells u that he want the file to appear like a funky format and he told u that the file is not changing ,what will u do ? there was an idea to run this
```
 $ sed 's/root/root and dude  /' apps_list
```
try to save the output.
1. Command line completion
2. File Operating and filtering-determine file contents-.
```
 $ cat file_name
```
```
 $ less file_name
```
```
 $ more file_name
```
```
 $ head file_name
```
```
 $ tail file_name
```
  using grep , cut ,paste , sort , diff , uniq wc ,aspell.
```
 $ sort -t : -k 3 -k 3 -n /etc/passwd
```
```
 $ wc -lcw filename
```
```
 $ cut -d: -f7  | sort| uniq
```
```
 $ paste -d: file_ids file_dates > merged_file
```
  1. Vi/Vim editor Introduction and running commands.
  2. Starting and handling background processes.
```
 $ jobs
```
```
 $ bg
```
```
 $ fg
```
    Using '&' to release console.
    1. Introduction to bash shell scripting .
  3. Scripting Basics
  4. Scripting Basics
  5. Create Shell scripts
  6. Making Script Executable
  7. Generating Output
  8. Handling Output
  9. Exit status
  10. Conditional Execution
```
note : 
```

&& = Logical AND || = Logical OR $ grep conceptor /etc/passwd || echo 'there is no conceptor entry'

Conditional Execution Using if Statement

I hope to finish all these topics , as far as I hope that audience understand them and practice.


!/bin/bash
read TIME
session_end='8:30'
if $TIME -lt $session_end 
 then 
           echo 'mount options , introduction to network commands'
else
	   echo 'See you later'
fi

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I think we need extra session

Submitted by mody on Wed, 18/08/2004 - 7:33pm.

I think we need extra session for bash scripting, the time was not enough , while it was very benifitable

important variables

Submitted by Alaa on Thu, 19/08/2004 - 12:14am.

$? holds the exit code or return code of the previous command

$! holds the pid of the most recent backgrounded command.

for instance in my .xinitrc file I have

pekwm& WMPID=$!
... #various desktop components
...
wait $WMPID

this way the window manager starts before anything else and I still get to make it the session manager (ie the session ends when pekwm terminates, due to the wait clause).

another interesting example of scripting is making inteligent bash prompts here is mine which is ripped from somewhere

export T_normal='1;34'
export T_bold=1
export T_underline=4
export C_owner='0;32'
export C_write='0;36'
export C_nowrite='0;31'
export C_error='0;31'
export DIRCOLOR=$T_normal
export EXIT_CODE=0
export CODE_COLOR='4;31'
export CODE_STRING=
export USER_STYLE=$T_normal
prompt_command()
{
   EXIT_CODE=$?
   DIRCOLOR=$T_normal
   # Color-code directory
   if -O &quot;$PWD&quot;
   then
      DIRCOLOR=$C_owner
   elif -w &quot;$PWD&quot;
   then
      DIRCOLOR=$C_write
   else
      DIRCOLOR=$C_nowrite
   fi
   # Add a bold red number for exitcode if its nonzero
   if $EXIT_CODE -ne 0
   then
      #CODE_COLOR=$C_error
      CODE_STRING=\($EXIT_CODE\)
   else
      #CODE_COLOR=$T_normal
      CODE_STRING=
   fi
   # Underline username if ssh-agent is running
   if -S &quot;$SSH_AUTH_SOCK&quot;
   then
      USER_STYLE=$T_underline
   else
      USER_STYLE=$T_normal
   fi
}
export PROMPT_COMMAND=prompt_command
if ${TERM:0:5} = xterm
then
   PS1='\\e0;\u@\h:\w\007\]'
else
   PS1=''
fi
if ${TERM:0:5} = dumb
then
    PS1='\u::\w$CODE_STRING$ '
else 
    PS1=$PS1'\\e[${USER_STYLE}m\\u\\e[0;35m::\[\e[${DIRCOLOR}m\\w\\e[${CODE_COLOR}m\$CODE_STRING\\e[0;35m\$\\e[0;m\ '
fi
export PS1

the funky bits are color codes ignore them.

cheers,

Alaa

http://www.manalaa.net

"u know i once dream that the office of mobinil is from el 7`os :S and the one that answer u and tell u rasidak a girl called ghada"

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Command Line session 2

I think we need extra session

important variables

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