i am just starting to learn about shell scripts, and i thought it would be cool if i could make a "paranoia" script that would erase certain directories on my system (but in the background so as to be relatively hidden). right now i am using one of my music folders for a test run (it's a copy; don't want to really lose my tunes!) because it is a very large directory (like 15GB). I was wondering, can i somehow use /dev/null for something like this? if i use
^^^^^^(don't use unless you're SURE you want to delete the directory in question!!!)
on that directory i think it would probably take a while... i'd want the fastest way possible, so i thought /dev/null might be an option... just a thought. any ideas?
Maybe it's an stupid question but remeber... I'm Junior..
I use command line to run programs, and some of them gives a lot of information when, for example, you open a window or other actions. That's really bad because my terminal gets full of unwanted messages, so I use "bin file & >/dev/null"... (1 Reply)
Hi,
Q1-What does
nroff -ms > /dev/null
Q2- What does mean -A under STAT column :
ps aux |head -20
UTIL PID %CPU %MEM SZ RSS TTY STAT STIME TIME COMMAND
root 516 93,0 0,0 12 12 - A 04 nov 3906:51 wait
Thank you. (4 Replies)
hello all,
In many shell scripts i found '> /dev/null' , i am not able to get this,
will any one please explain why we are using this.
thanks
sudha (2 Replies)
Hi, Anyone can help
My solaris 8 system has the following
/dev/null , /dev/tty and /dev/console
All permission are lrwxrwxrwx
Can this be change to a non-world write ??
any impact ?? (12 Replies)
Hi expert,
May I know what is the difference between below cron tab entry ?
0,12 * * * * /abc/myscript.sh > /dev/null 2>&1
0,12 * * * * /abc/myscript.sh (7 Replies)
How are these two different? They both prevent output and error from being displayed. I don't see the use of the "&"
echo "hello" > /dev/null 2>&1
echo "hello" > /dev/null 2>1 (3 Replies)
I apologize if this question has been answered else where or is too elementary.
I ran across a KSH script (long unimportant story) that does this:
if ; then
CAS_SRC_LOG="/var/log/cas_src.log 2>&1"
else
CAS_SRC_LOG="/dev/null 2>&1"
fithen does this:
/usr/bin/echo "heartbeat:... (5 Replies)
Hello All and a Happy New year to yous guys.
I'm running the below command on my AIX box and it keeps giving me the message that the file doesn't exist. I know the file don't exist, but I don't want to see the error. 2>/dev/null doesn't work.
bash-3.00$ ls -l C* | wc -l 2>/dev/null
ls:... (2 Replies)
Discussion started by: bbbngowc
2 Replies
LEARN ABOUT BSD
learn
LEARN(1) General Commands Manual LEARN(1)NAME
learn - computer aided instruction about UNIX
SYNOPSIS
learn [ -directory ] [ subject [ lesson ] ]
DESCRIPTION
Learn gives Computer Aided Instruction courses and practice in the use of UNIX, the C Shell, and the Berkeley text editors. To get started
simply type learn. If you had used learn before and left your last session without completing a subject, the program will use information
in $HOME/.learnrc to start you up in the same place you left off. Your first time through, learn will ask questions to find out what you
want to do. Some questions may be bypassed by naming a subject, and more yet by naming a lesson. You may enter the lesson as a number
that learn gave you in a previous session. If you do not know the lesson number, you may enter the lesson as a word, and learn will look
for the first lesson containing it. If the lesson is `-', learn prompts for each lesson; this is useful for debugging.
The subject's presently handled are
files
editor
vi
morefiles
macros
eqn
C
There are a few special commands. The command `bye' terminates a learn session and `where' tells you of your progress, with `where m'
telling you more. The command `again' re-displays the text of the lesson and `again lesson' lets you review lesson. There is no way for
learn to tell you the answers it expects in English, however, the command `hint' prints the last part of the lesson script used to evaluate
a response, while `hint m' prints the whole lesson script. This is useful for debugging lessons and might possibly give you an idea about
what it expects.
The -directory option allows one to exercise a script in a nonstandard place.
FILES
/usr/share/learn subtree for all dependent directories and files
/usr/tmp/pl* playpen directories
$HOME/.learnrc startup information
SEE ALSO csh(1), ex(1)
B. W. Kernighan and M. E. Lesk, LEARN - Computer-Aided Instruction on UNIX
BUGS
The main strength of learn, that it asks the student to use the real UNIX, also makes possible baffling mistakes. It is helpful, espe-
cially for nonprogrammers, to have a UNIX initiate near at hand during the first sessions.
Occasionally lessons are incorrect, sometimes because the local version of a command operates in a non-standard way. Occasionally a lesson
script does not recognize all the different correct responses, in which case the `hint' command may be useful. Such lessons may be skipped
with the `skip' command, but it takes some sophistication to recognize the situation.
To find a lesson given as a word, learn does a simple fgrep(1) through the lessons. It is unclear whether this sort of subject indexing is
better than none.
Spawning a new shell is required for each of many user and internal functions.
The `vi' lessons are provided separately from the others. To use them see your system administrator.
7th Edition October 22, 1996 LEARN(1)