Carding the basic knowledge of shell script & lt; V & gt;: process Control case
Case uses format
Case value in
Mode 1)
Instruction 1
Instruction 2
...
Mode 2)
Instruction 1
Instruction 2
...
Esca
Echo 'enter a number between 1 and 4:'
Echo 'the number you entered is:'
Read aNum
Case $aNum in
1) echo 'you chose 1'
2) echo 'you chose 2'
3) echo 'you chose 3'
4) echo 'you chose 4'
*) echo 'you did not enter a number between 1 and 4'
Esac
Example 1
#! / bin/bash
# case...esac
Echo "What is your preferred scripting language?"
Echo "1) bash"
Echo "2) prel"
Echo "3) python"
Echo "4) ruby"
Echo "5) I do not know!"
Read lang
Case $lang in
1) echo "you selected bash"
2) echo "you selected prel"
3)
Echo "you selected python"
4)
Echo "you selected ruby"
5)
Echo "I do not know!"
Esac
Execution result
[root@localhost shell] # sh case.sh
What is your preferred scripting language?
1) bash
2) prel
3) python
4) ruby
5) I do not know!
four
You selected ruby
[root@localhost shell] # sh case.sh
What is your preferred scripting language?
1) bash
2) prel
3) python
4) ruby
5) I do not know!
five
I do not know!
[root@localhost shell] #
Example 2
#! / bin/bash
Echo-n "Do you agree whith this? [yes or no]:"
Read yn
Case $yn in
[Yy] | [Yy] [Ee] [Ss])
Echo "Agreed."
[Nn] | [Nn] [Oo])
Echo "Not Agreed."
Exit 1
*)
Echo "Invalid input."
Esac
Running result:
[root@localhost shell] # sh case2.sh
Do you agree whith this? [yes or no]: 1
Invalid input.
[root@localhost shell] # sh case2.sh
Do you agree whith this? [yes or no]: n
Not Agreed.
[root@localhost shell] # sh case2.sh
Do you agree whith this? [yes or no]: Yes
Agreed.
[root@localhost shell] #
Example 3
#! / bin/bash
Case $1 in
Sql) echo "Runing mysql backup using mysqldump tool..."
Sync) echo "Runing backup using rsyuc tool..."
Git) echo "Runing backup using gistore tool..."
Tar) echo "Runing tape backup using tar tool..."
*)
Echo "Backup shell script utility"
Echo "Usage: $0 {sql | sync | git | tar}"
Echo "sql: Run mysql backup utility."
Echo "sync: Run web backup utility."
Echo "git: Run gistore backup utility."
Echo "tar: Run tape backup utility."
Esac
Running result:
[root@localhost shell] # sh case3.sh
Backup shell script utility
Usage: case3.sh {sql | sync | git | tar}
Sql: Run mysql backup utility.
Sync: Run web backup utility.
Git: Run gistore backup utility.
Tar: Run tape backup utility.
[root@localhost shell] # sh case3.sh sql
Runing mysql backup using mysqldump tool...
[root@localhost shell] #
Example 4
#! / bin/bash
# get the one with the highest disk utilization
Max_usage=$ (df-Ph | awk'{print $5}'| grep% | grep-v "Use" | sort-n | tail-1 | cut-d "%"-F1)
Max_dir=df-Ph | awk'{print $5 print 6}'| grep-v Use | sort-n | tail-1 | awk'{print $2}'
Case ${max_usage} in
[1-6])
MSG= "All is quiet.\" ${max_dir}\ "is ${max_usage}% used"
[7-8])
MSG= "Start thinking about cleaning out some stuff."
MSG= "$MSG There's a partition ${max_dir} is ${max_usage}% used."
9 [1-8])
MSG= "Better hurry with that new disk..."
MSG= "$MSG One partition ${max_dir} is ${max_usage}% used."
99)
MSG= "I'm drowning herel There's a partiton at ${max_usage} used"
)
MSG= "I seem to be runing with an nonexitent amount of disk space..."
Esac
# echo $MSG | mail-s "disk report date" root
Echo $MSG
Running result:
[root@localhost shell] # sh case4.sh
All is quiet. "/" is 22% used
[root@localhost shell] #
