Sick of your computer speaker beeping like a demented Morse code machine whenever you type something wrongly? Teach it the sound of silence: run the command
setterm -blength 0
to mute the alarm bell no matter what kind of terminal you're typing into.
If you want it to happen every time you start a terminal, just add the command to your .bash_profile file.

generate a list of IP address along with the number of times each was encountered and sort

cat access_log | awk '{print $1}' | sort | uniq -c | sort -nr

#!/bin/sh
tar czvf $1.$(date +%Y%m%d-%H%M%S).tgz $1
exit $?

The arc script accepts a single file or directory name as a parameter and creates a compressed archive file with the current date embedded into the resulting archive file's name.

# at -v 03:00 -f /root/shantanu/testat.sh > /root/shantanu/testat_result.txt 2>&1
# atq
7 2009-03-14 03:00 a root

`test -s /var/log/mailme.txt`
if [[ $? -eq 0 ]] ; then
The above 2 lines can be written in one line as shown below:

if [[ -z /var/log/mailme.txt ]]; then

#!/bin/sh
awk -F"," '{print $1,$2}' read1.txt | while read var1 var2
do
echo $var1 $var2
done

30 0 * * * updatedb > /dev/null 2>&1

# Clock synchronization
30 10 * * * CTIPDGT=`/sbin/ifconfig | grep -m 1 "inet addr" | grep -o "17.2.[0,8,26,32,40,56,16,40,56].*" | cut -d "." -f3`; /usr/sbin/ntpdate -u 172.29.${CTIPDGT}.123; /sbin/hwclock --systohc > /dev/null 2>&1

The declare command can be helpful in identifying variables, environmental or otherwise. This can be especially useful with arrays.

bash$ declare | grep HOME
/home/bozo

bash$ zzy=68
bash$ declare | grep zzy
zzy=68

bash$ Colors=([0]="purple" [1]="reddish-orange" [2]="light green")
bash$ echo ${Colors[@]}
purple reddish-orange light green
bash$ declare | grep Colors
Colors=([0]="purple" [1]="reddish-orange" [2]="light green")

$ watch --interval=1 --differences 'mysql -uuser -ppassword -e "show slave status\G"'

# vi /bin/findtable

#!bin/sh

mysql -e"select TABLE_SCHEMA, TABLE_NAME, ENGINE, TABLE_ROWS, CREATE_TIME FROM information_schema.TABLES where TABLE_NAME LIKE '%$1%';"

# chmod 777 /bin/findtable

# sh findtable test