How to understand the find command

This article is about how to understand the find command, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Find command:

Find-search for files in a directory hierarchy

Find [OPTIONS...] [search path] [search condition] [processing action]

Search path: the default is the current working directory, and you can specify a specific directory path

Search criteria: the criteria for this search can be file name, file size, file type, file permissions, etc.; the default is all files in the specified directory

Processing action: perform a processing operation on files that meet the criteria; output the search results to the monitor by default

Look up by file name:

-name file name, which supports the use of Globbing, (*,?, [], [^]), and search based on keywords.

Example: [root@localhost test] # find. -name "* .log"

. / log_link.log

. / log2014.log

-iname file name, ignore the case of letters, support the use of Globbing, (*,?, [], [^])

Example: find /-iname qin

Look up according to the inode number of the file:

-inum inode number: find the corresponding file name and path through the given inode number

-samefile name: find the corresponding inode number through the given file name, and then determine all the file names and paths with the inode number

-links n: find all files with n links

Look up according to the regular expression:

-regex pattern: matches the entire file path string with pattern, not just the name of the given file

Search according to the owner and group of the file:

-user uname: search based on the user name of the specified user by the owner

-uid UID: search for a UID based on the owner

-group gname:

-gid GID:

-nogroup: there is no group name corresponding to the group in the file.

-nouser: there is no corresponding user name on the owner of the file

Look up according to the type of file:

-type file type:

B: block equipment

C: character device

D: catalog file

F: ordinary files

L: symbolic link file

P: pipe fil

S: socket file

-xtype file type: matching of symbolic link files needs to be matched with other options

Look up according to the timestamp:

In days:

-atime [+ | -] n: search based on access time

-ctime [+ | -] n: search according to the change time

-mtime [+ | -] n: search based on modification time

N: [NJ Numer1)

+ n: [nasty 1pm + ∞)

-n: [now,n)

In minutes:

-amin [+ | -] n

-cmin [+ | -] n

-mmin [+ | -] n

Example: find files in the / etc directory that have been modified in the last week and do not belong to root and suse users

Find / etc-ctime-7-a-user root-a-user suse

Example: look for files with a change time before 5 days in the / l o g s directory and delete them:

Find logs-type f-mtime + 5-exec-ok rm {}\

Look up according to the size of the file:

-size [+ | -] n [cwbkMG]

N: (n Mei 1Jing n]

-n: [05m nmuri 1]

+ n: (NMagna + ∞)

Example:

Find-size + 2k

All files greater than 2KB in the current directory

Find-size 2k

Files between all 1KB-2KB in the current directory

Find-size-2k

All files smaller than 1KB in the current directory

Combination conditions:

-a: logic and, by default, can be omitted

-o: logical or

-not,!: logic not

Example: find files in the / usr directory that do not belong to root, bin, centos and other users

Find / usr-not-user root-a-not-user bin-a-not-user centos

The logical combination conditions follow de Morgan's law:

Not (An and B) = not An or B

Non (An or B) = non-An and non-B

Find based on permissions:

-perm [/ | -] mode

Mode: exactly matches the specified permissions

/ mode: the logical OR relationship is implied. The condition can be satisfied as long as there is a permission match in any permission bit.

-mode: implies the relationship between logic and. The permission of each permission bit must also contain the specified permission bit in order to meet the condition.

Example: find files in the / etc/rc.d/init.d directory where all users have execute permissions and other users have write permissions

Find / etc/rc.d/init.d-prem / 111a-perm-002

All of them are against any one of them.

! (an and b and c) =! an or! B or! C

None of them are reversed. Any one of them has.

! (! an and! B and! C) = an or b or c

Processing actions:

-print: output to the display screen, default action

-ls: execute the ls-li command to display the results found

Example: look for files in the / etc directory that all users do not have write permission to, and display their details

Find / etc-not-perm / 222-ls

-exec COMMAND {}\;:

-ok COMMAND {}\;:

Execute the COMMAND command for the found results

Difference:

-exec is non-interactive

-ok is interactive

{}: placeholder to refer to the path information of all files found by the find command

Ex.: find files that do not have owners or groups on the current system and have been accessed in the last month, and change them to root

Find /-nouser-o nogroup-a-atime-30-exec chown root:root {}\

Instead of performing operations,-exec and-ok:

Chmod Amurr $(find-perm-444-type f)

Find-perm-444-type f | xargs chmod Amurr

Note: the pipeline carries pure string information, so if the command after the pipe is not a command for processing strings, you need to use the xargs command to convert it into parameters that can be processed by subsequent commands.

Example: look for all * .h in / tmp, look for "SYSCALL_VECTOR" in these files, and finally print out all the file names that contain "SYSCALL_VECTOR"

Find / tmp-name "* .h" | xargs-n50 grep SYSCALL_VECTOR

The above is how to understand the find command, the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.