Conditional statements: finding folders that don't contain a particular file
1
I needed to find all folders, whose names have a digit in them, that don't contain a file ending with .counts.txt. By combining several suggestions I found online, I was able to come up with the following command (for bash), which does what I want.
find . maxdepth 1 -type d -name "*[0-9]*" ! -exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ; -print
However, I don't understand some of its features:
- What does the exclamation mark do here? Does it somehow negate the condition statement that follows?
- Why is it necessary to open a new shell using
shrather than directly piping tols?
files find directory ls
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
add a comment |
1
I needed to find all folders, whose names have a digit in them, that don't contain a file ending with .counts.txt. By combining several suggestions I found online, I was able to come up with the following command (for bash), which does what I want.
find . maxdepth 1 -type d -name "*[0-9]*" ! -exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ; -print
However, I don't understand some of its features:
- What does the exclamation mark do here? Does it somehow negate the condition statement that follows?
- Why is it necessary to open a new shell using
shrather than directly piping tols?
files find directory ls
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
add a comment |
1
1
1
1
I needed to find all folders, whose names have a digit in them, that don't contain a file ending with .counts.txt. By combining several suggestions I found online, I was able to come up with the following command (for bash), which does what I want.
find . maxdepth 1 -type d -name "*[0-9]*" ! -exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ; -print
However, I don't understand some of its features:
- What does the exclamation mark do here? Does it somehow negate the condition statement that follows?
- Why is it necessary to open a new shell using
shrather than directly piping tols?
files find directory ls
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
I needed to find all folders, whose names have a digit in them, that don't contain a file ending with .counts.txt. By combining several suggestions I found online, I was able to come up with the following command (for bash), which does what I want.
find . maxdepth 1 -type d -name "*[0-9]*" ! -exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ; -print
However, I don't understand some of its features:
- What does the exclamation mark do here? Does it somehow negate the condition statement that follows?
- Why is it necessary to open a new shell using
shrather than directly piping tols?
files find directory ls
files find directory ls
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
edited Dec 16 at 4:24
Rui F Ribeiro
38.9k1479129
38.9k1479129
asked Jul 15 '17 at 10:19
GingerBadger
1083
asked Jul 15 '17 at 10:19
GingerBadger
1083
asked Jul 15 '17 at 10:19
GingerBadger
1083
1083
add a comment |
add a comment |
1 Answer
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- Yes the
!negates the next condition, that is the-exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ;. As this is an-execcondition that is negated we have to remeber that it is true if the command it executes returns with status 0 (and negated the condition is true if the status is not 0). - The arguments after
-execare not passed to a shell but instead are executed directly so there is no concept of a pipe available. If you would put a pipe character there the outer shell (which started find itself) would use that and all the output from find would go to egrep.
See man find for the docs on the ! and -exec args for find.
answered Jul 15 '17 at 11:23
Lucas
1,988717
add a comment |
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1 Answer
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- Yes the
!negates the next condition, that is the-exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ;. As this is an-execcondition that is negated we have to remeber that it is true if the command it executes returns with status 0 (and negated the condition is true if the status is not 0). - The arguments after
-execare not passed to a shell but instead are executed directly so there is no concept of a pipe available. If you would put a pipe character there the outer shell (which started find itself) would use that and all the output from find would go to egrep.
See man find for the docs on the ! and -exec args for find.
answered Jul 15 '17 at 11:23
Lucas
1,988717
add a comment |
1
- Yes the
!negates the next condition, that is the-exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ;. As this is an-execcondition that is negated we have to remeber that it is true if the command it executes returns with status 0 (and negated the condition is true if the status is not 0). - The arguments after
-execare not passed to a shell but instead are executed directly so there is no concept of a pipe available. If you would put a pipe character there the outer shell (which started find itself) would use that and all the output from find would go to egrep.
See man find for the docs on the ! and -exec args for find.
answered Jul 15 '17 at 11:23
Lucas
1,988717
add a comment |
1
1
1
- Yes the
!negates the next condition, that is the-exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ;. As this is an-execcondition that is negated we have to remeber that it is true if the command it executes returns with status 0 (and negated the condition is true if the status is not 0). - The arguments after
-execare not passed to a shell but instead are executed directly so there is no concept of a pipe available. If you would put a pipe character there the outer shell (which started find itself) would use that and all the output from find would go to egrep.
See man find for the docs on the ! and -exec args for find.
answered Jul 15 '17 at 11:23
Lucas
1,988717
- Yes the
!negates the next condition, that is the-exec sh -c 'ls -1 "{}" | egrep -q "*.counts.txt"' ;. As this is an-execcondition that is negated we have to remeber that it is true if the command it executes returns with status 0 (and negated the condition is true if the status is not 0). - The arguments after
-execare not passed to a shell but instead are executed directly so there is no concept of a pipe available. If you would put a pipe character there the outer shell (which started find itself) would use that and all the output from find would go to egrep.
See man find for the docs on the ! and -exec args for find.
answered Jul 15 '17 at 11:23
Lucas
1,988717
answered Jul 15 '17 at 11:23
Lucas
1,988717
answered Jul 15 '17 at 11:23
Lucas
1,988717
answered Jul 15 '17 at 11:23
Lucas
1,988717
1,988717
add a comment |
add a comment |
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