10 . مقایسه در bash
10. 1. مقایسه حسابی
| -lt |
|
| -gt |
> |
| -le |
|
| -ge |
>= |
| -eq |
== |
| -ne |
!= |
#!/bin/bash
# declare integers
NUM1=2
NUM2=2
if [ $NUM1 -eq $NUM2 ]; then
echo "Both Values are equal"
else
echo "Values are NOT equal"
fi
#!/bin/bash
# declare integers
NUM1=2
NUM2=1
if [ $NUM1 -eq $NUM2 ]; then
echo "Both Values are equal"
else
echo "Values are NOT equal"
fi
#!/bin/bash
# declare integers
NUM1=2
NUM2=1
if [ $NUM1 -eq $NUM2 ]; then
echo "Both Values are equal"
elif [ $NUM1 -gt $NUM2 ]; then
echo "NUM1 is greater then NUM2"
else
echo "NUM2 is greater then NUM1"
fi
10.2. مقایسه رشته
| = |
برابر |
| != |
نابرابر |
|
|
کمتر از |
| > |
بزرگتر از |
| -n s1 |
رشته s1 خالی نیست |
| -z s1 |
رشته s1 خالی است |
#!/bin/bash
#Declare string S1
S1="Bash"
#Declare string S2
S2="Scripting"
if [ $S1 = $S2 ]; then
echo "Both Strings are equal"
else
echo "Strings are NOT equal"
fi
#!/bin/bash
#Declare string S1
S1="Bash"
#Declare string S2
S2="Bash"
if [ $S1 = $S2 ]; then
echo "Both Strings are equal"
else
echo "Strings are NOT equal"
fi
11. تست فایل در bash
-b filename Block special file
-c filename Special character file
-d directoryname Check for directory existence
-e filename Check for file existence
-f filename Check for regular file existence not a directory
-G filename Check if file exists and is owned by effective group ID.
-g filename true if file exists and is set-group-id.
-k filename Sticky bit
-L filename Symbolic link
-O filename True if file exists and is owned by the effective user id.
-r filename Check if file is a readable
-S filename Check if file is socket
-s filename Check if file is nonzero size
-u filename Check if file set-ser-id bit is set
-w filename Check if file is writable
-x filename Check if file is executable
#!/bin/bash
file="./file"
if [ -e $file ]; then
echo "File exists"
else
echo "File does not exists"
fi
به طور مشابه برای مثال شما می توانید اط حلقه while loop برای اینکه بررسی کنید که فایلی ساخته نشده است اتفاده نمایید ، این اسکریپت در حالت sleep می ماند تا فایلی ایجاد نشده است، برای نفی کردن دستور از علامت ! استفاده می شود مثلا علامت ! در کنار گزینه e بر عکس گزینه e را انجام می دهد.
#!/bin/bash
while [ ! -e myfile ]; do
# Sleep until file does exists/is created
sleep 1
done
12. حلقه
12.1. حلقه for در bash
#!/bin/bash
# bash for loop
for f in $( ls /var/ ); do
echo $f
done
اجرای حلقه for در bash shell command line:
$ for f in $( ls /var/ ); do echo $f; done
12.2. حلقه while در bash
#!/bin/bash
COUNT=6
# bash while loop
while [ $COUNT -gt 0 ]; do
echo Value of count is: $COUNT
let COUNT=COUNT-1
done
12.3. حلقه until در bash
#!/bin/bash
COUNT=0
# bash until loop
until [ $COUNT -gt 5 ]; do
echo Value of count is: $COUNT
let COUNT=COUNT+1
done
12.4. کنترل bash loop with
در اینجا یک مثال در حالی که حلقه توسط ورودی استاندارد کنترل می شود. تا زنجیره تغییر مسیر از STDOUT به STDIN به دستور خواندن وجود دارد حلقه while ادامه می دهد.
#!/bin/bash
# This bash script will locate and replace spaces
# in the filenames
DIR="."
# Controlling a loop with bash read command by redirecting STDOUT as
# a STDIN to while loop
# find will not truncate filenames containing spaces
find $DIR -type f | while read file; do
# using POSIX class [:space:] to find space in the filename
if [[ "$file" = *[[:space:]]* ]]; then
# substitute space with "_" character and consequently rename the file
mv "$file" `echo $file | tr ' ' '_'`
fi;
# end of while loop
done
13. توابع در bash
!/bin/bash
# BASH FUNCTIONS CAN BE DECLARED IN ANY ORDER
function function_B {
echo Function B.
}
function function_A {
echo $1
}
function function_D {
echo Function D.
}
function function_C {
echo $1
}
# FUNCTION CALLS
# Pass parameter to function A
function_A "Function A."
function_B
# Pass parameter to function C
function_C "Function C."
function_D
14. انتخاب در bash
#!/bin/bash
PS3='Choose one word: '
# bash select
select word in "linux" "bash" "scripting" "tutorial"
do
echo "The word you have selected is: $word"
# Break, otherwise endless loop
break
done
exit 0
15. انتخاب یک گزینه به صورت شرطی
#!/bin/bash
echo "What is your preferred programming / scripting language"
echo "1) bash"
echo "2) perl"
echo "3) phyton"
echo "4) c++"
echo "5) I do not know !"
read case;
#simple case bash structure
# note in this case $case is variable and does not have to
# be named case this is just an example
case $case in
1) echo "You selected bash";;
2) echo "You selected perl";;
3) echo "You selected phyton";;
4) echo "You selected c++";;
5) exit
esac
