Using Linux Find

Question

I'd like to find the MAIN.TXT file in a directory folder. If it is older than 24hours then output YES to the MAIN.txt file. If it hasn't been modified in 24hours then leave the file alone.

I got as far as this:

find /directory -type f -mtime +1 -exec echo 'YES' > /directory/MAIN.txt \;

The MAIN.TXT file is older than 24 hours, so it works. This updates MAIN.TXT mod time to the current time and my MAIN.txt file has YES in it.

If MAIN.TXT is newer than 24hours old, it still modifies the MAIN.TXT with blank txt and changed the modification time.

I know I need a conditional, but I can't seem to get where it goes. Additionally, my mentor mentioned {} for my ECHO parameter but if I do that, then I get the filename with AVAILABLE appended.

Answer 1

Mark's answer seems to fall a little short of OP's requirements.

Try this one liner at your terminal prompt. It is simpler and probably more robust.

[ $(find /path/to/directory/. -maxdepth 1 -type f -name MAIN.TXT -daystart -mtime +1) ] \
  && printf "YES" > /full/path/to/directory/MAIN.TXT

A word of explanation, first looking the larger blocks of the one liner, then getting into each block:

• the one liner as the form [ block1 ] && block2
• the construct [ block1 ] (with spaces!) is a boolean logical operator equivalent to the test built-in.
• If block1's execution returns something (anything) then the result of [ block1 ] is TRUE. If it returns nothing, as in "", then the previous test's result is FALSE.
• the logical operator && in A && B reflects the fact that B is executed if the exit status of A is 0 or TRUE. So if [ block1 ] executes to TRUE, then block2 is also executed.
• block1 as the form $( ). This is a command substitution. Everything that is inside the parentheses is executed and the output replaces the command. That is the reason it is called "command substitution".
• inside block1 the cmd being substituted consists in finding a file:
  • whose type is regular file
  • named MAIN.TXT
  • inside the directory /path/to/directory/.
  • no further down than the very directory level specified above (-maxdepth 1)
  • whose modification time is at least 24 hours (-mtime +1) starting from TODAY's time (-daystart). Without -daystart your search would look for files modified more that 24 hours ago, but starting to count backward from yesterday's 0 hour time.

Answer 2

[ $(find /directory -type f -mtime +1 | wc -l) -gt 0 ] && echo 'YES' > /directory/MAIN.txt