Make sure that only one process is running in shell.

In Shell, only one process can be implemented at a time:

 

1. lockf command

 

2. Simple implementation:

I = 'ps-Ef | grep [N] ew_mvbackup | WC-l' if [$ I-GT 1];
Then
Echo "wait for the other mvbackup finish! "
Exit-1
Else

# Do something here

 

3. Another implementation:

Lock_on ()

{

Local F = $1

Local freefd = 6 # Do not use FD 5

# Make sure the file be there

Mkdir-P "$ (dirname $ f )"

Touch "$ F"

# Find a free FD

While (freefd <= 9); do

[[-L/dev/FD/$ freefd] | break

(Freefd ++ ))

Done

 

(Freefd = 10) & return 1

# Open the lock file

Eval "Exec $ freefd </" $ F /""
}

 

Is_locked ()

{

Local F = $1

Fuser "$ F" &>/dev/null

}

Lock = "/tmp/. $ (basename $0). Lock"

Is_locked "$ lock" & Exit 1

Lock_on "$ lock"

 

# Do something here