Ubuntu Unleashed 2019 Edition: Covering 18.04, 18.10, 19.04

You can then easily play back a voice message by using this script (in this case named pmm): Click h ...

# record log search start echo "Search for->" $1 "starting" `date '+%r'` >>$log_report echo "" >> ...

S Y S T E M M O N I T O R L O G Linux ...

you get the following result: Click here to view code image Number of parameters is 2 Program name is mypg ...

[a-z] Specifies all characters a through z [a,z] or [az] Specifies characters a or z Space Acts as a delimiter ...

set x=“abc def”tcsh The double quotes resolve all variables within the string. Here is an example for pdksh and bas ...

Click here to view code image Value of var is $var As you can see, the variable var maintains its origi ...

execution of a command to be stored in a variable. For example, if you want to count the number of lines ...

String Comparison You can use the following operators to compare two string expressions: =—Compares whether two string ...

string1 not equal to string2 string2 not equal to string1 string1 is not empty string2 has a length greater than ze ...

if [ $number1 -gt $number2 ]; then echo "number1 is greater than number2" else echo ...

called file1 and a subdirectory dir1 under the current directory. Assume that file1 has a permission of r ...

is, comparing values using characters representing NOT, AND, and OR: !—Negates a logical expression -a—Logica ...

==—Compares whether two strings are equal !=—Compares whether two strings are not equal The following examples compare two ...

set number2=10 set number3=5 if (number1 > number2) then echo "number1 is greater than ...

-x—Determines whether execute permission is set for a file -z—Determines whether the file size is zero The follow ...

If you execute the file compare3, you get the following results: Click here to view code image dir1 is a ...

The for Statement You use the for statement to execute a set of commands once each time a specified condi ...

for each iteration, the current value of list is assigned to curvar. Suppose that you want to create a ...

while : do /sbin/iwconfig eth0 | grep Link | tr '\n' '\r' Done The script outputs t ...