查找文件并执行的shell命令
来由
经常我们需要找到某类文件, 并对进行处理。 例如找到.svn文件夹, 然后删除掉。 如果不使用shell,你可以选择手动删除, 前提是没有几个此类文件, 但是svn信息文件很多, 不能采用手动删除, 或者逐个命令删除。
由此引入shell来解决此问题。
方法1 find –exec 选项
NAME
find - search for files in a directory hierarchySYNOPSIS
find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]DESCRIPTION
This manual page documents the GNU version of find. GNU find searches the
directory tree rooted at each given file name by evaluating the given expres‐
sion from left to right, according to the rules of precedence (see section
OPERATORS), until the outcome is known (the left hand side is false for and
operations, true for or), at which point find moves on to the next file name.If you are using find in an environment where security is important (for exam‐
ple if you are using it to search directories that are writable by other
users), you should read the "Security Considerations" chapter of the findutils
documentation, which is called Finding Files and comes with findutils. That
document also includes a lot more detail and discussion than this manual page,
so you may find it a more useful source of information.
有效命令:
find ./testtime/ -name .svn -exec rm -rf {}\;;
-exec command ;
Execute command; true if 0 status is returned. All following arguments
to find are taken to be arguments to the command until an argument con‐
sisting of `;' is encountered. The string `{}' is replaced by the cur‐
rent file name being processed everywhere it occurs in the arguments to
the command, not just in arguments where it is alone, as in some ver‐
sions of find. Both of these constructions might need to be escaped
(with a `\') or quoted to protect them from expansion by the shell.
See the EXAMPLES section for examples of the use of the -exec option.
The specified command is run once for each matched file. The command
is executed in the starting directory. There are unavoidable security
problems surrounding use of the -exec action; you should use the
-execdir option instead.-exec command {} +
This variant of the -exec action runs the specified command on the
selected files, but the command line is built by appending each
selected file name at the end; the total number of invocations of the
command will be much less than the number of matched files. The com‐
mand line is built in much the same way that xargs builds its command
lines. Only one instance of `{}' is allowed within the command. The
command is executed in the starting directory.
方法2 find xargs组合
xargs 含义, 从xargs参数构造命令,并执行, 执行命令的入参为标准输入。
NAME
xargs - build and execute command lines from standard inputSYNOPSIS
xargs [-0prtx] [-E eof-str] [-e[eof-str]] [--eof[=eof-str]] [--null] [-d
delimiter] [--delimiter delimiter] [-I replace-str] [-i[replace-str]]
[--replace[=replace-str]] [-l[max-lines]] [-L max-lines] [--max-lines[=max-
lines]] [-n max-args] [--max-args=max-args] [-s max-chars] [--max-chars=max-
chars] [-P max-procs] [--max-procs=max-procs] [--interactive] [--verbose]
[--exit] [--no-run-if-empty] [--arg-file=file] [--show-limits] [--version]
[--help] [command [initial-arguments]]DESCRIPTION
This manual page documents the GNU version of xargs. xargs reads items from
the standard input, delimited by blanks (which can be protected with double or
single quotes or a backslash) or newlines, and executes the command (default
is /bin/echo) one or more times with any initial-arguments followed by items
read from standard input. Blank lines on the standard input are ignored.Because Unix filenames can contain blanks and newlines, this default behaviour
is often problematic; filenames containing blanks and/or newlines are incor‐
rectly processed by xargs. In these situations it is better to use the -0 op‐
tion, which prevents such problems. When using this option you will need to
ensure that the program which produces the input for xargs also uses a null
character as a separator. If that program is GNU find for example, the
-print0 option does this for you.If any invocation of the command exits with a status of 255, xargs will stop
immediately without reading any further input. An error message is issued on
stderr when this happens.
有效命令:
find -name .svn | xargs rm –rf
方法3 find –delete选项
比前面两个更有效率。
find /tmp -depth -name core -type f -delete
Find files named core in or below the directory /tmp and delete them, but more
efficiently than in the previous example (because we avoid the need to use
fork(2) and exec(2) to launch rm and we don't need the extra xargs process).