bash - File Lock on Linux -


so there 2 scripts: , b, both want write same file. it's possible both scripts want write file @ same time. how can lock file? while script writing file, script b has wait till file unlocked.

i tried this: 

while [ -f $lock ]     sleep 0.1     done touch $lock #action rm $lock

problem script above it's possible, both of , b looking $lock @ same time, , cant find't start writing. help?

try this:

script open file set attribute chattr +i test.txt , after script done use chattr -i test.txt.

for example:

script a

chattr +i test.txt tail -n 50 /var/log/maillog > test.txt chattr -i test.txt

script b

chattr +i test.txt tail -n 50 /var/log/messages > test.txt chattr -i test.txt

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