1 .TH XARGS 1 \" -*- nroff -*-
3 xargs \- build and execute command lines from standard input
6 [\-0prtx] [\-E[eof-str]] [\-e[eof-str]] [\-\-eof[=eof-str]] [\-\-null]
7 [\-I[replace-str]] [\-i[replace-str]] [\-\-replace[=replace-str]]
8 [\-l[max-lines]] [\-L[max-lines]] [\-\-max\-lines[=max-lines]] [\-n max-args] [\-\-max\-args=max-args]
9 [\-s max-chars] [\-\-max\-chars=max-chars] [\-P max-procs] [\-\-max\-procs=max-procs]
10 [\-\-interactive] [\-\-verbose] [\-\-exit]
11 [\-\-no\-run\-if\-empty] [\-\-arg\-file=file] [\-\-version] [\-\-help]
12 [command [initial-arguments]]
15 documents the GNU version of
18 reads items from the standard input, delimited by blanks (which can be
19 protected with double or single quotes or a backslash) or newlines,
22 (default is /bin/echo) one or more times with any
24 followed by items read from standard input. Blank lines on the
25 standard input are ignored.
27 Because Unix filenames can contain blanks and newlines, this default
28 behaviour is often problematic; filenames containing blanks
29 and/or newlines are incorrectly processed by
31 In these situations it is better to use the `\-0' option, which
32 prevents such problems. When using this option you will need to
33 ensure that the program which produces the input for
35 also uses a null character as a separator. If that program is
38 for example, the `\-print0' option does this for you.
40 If any invocation of the command exits with a status of 255,
42 will stop immediately without reading any further input. An error
43 message is issued on stderr when this happens.
46 .I "\-\-arg\-file=file, \-a file"
49 instead of standard input. If you use this option, stdin remains
50 unchanged when commands are run. Otherwise, stdin is redirected
56 Input items are terminated by a null character instead of by
57 whitespace, and the quotes and backslash are not special (every
58 character is taken literally). Disables the end of file string, which
59 is treated like any other argument. Useful when input items might
60 contain white space, quote marks, or backslashes. The GNU find
61 \-print0 option produces input suitable for this mode.
63 .I "\-\-eof[=eof-str], \-E[eof-str]"
64 Set the end of file string to \fIeof-str\fR. If the end of file
65 string occurs as a line of input, the rest of the input is ignored.
66 If \fIeof-str\fR is omitted, there is no end of file string. If this
67 option is not given, no end of file string is used.
70 This option is a synonym for the `\-E' option. Use `\-E' instead,
71 because it is POSIX compliant while this option is not.
74 Print a summary of the options to
78 .I "\-\-replace[=replace-str], \-i[replace-str]"
79 Replace occurrences of \fIreplace-str\fR in the initial-arguments with
80 names read from standard input.
81 Also, unquoted blanks do not terminate input items; instead the
82 separator is the newline character.
83 If \fIreplace-str\fR is omitted, it
84 defaults to "{}" (like for `find \-exec'). Implies \fI\-x\fP and
87 .I "\-\-max\-lines[=max-lines], \-L[max-lines]"
88 Use at most \fImax-lines\fR nonblank input lines per command line;
89 \fImax-lines\fR defaults to 1 if omitted. Trailing blanks cause an
90 input line to be logically continued on the next input line. Implies
94 Deprecated; non-POSIX-compliant synonym for the
98 .I "\-\-max\-args=max-args, \-n max-args"
99 Use at most \fImax-args\fR arguments per command line. Fewer than
100 \fImax-args\fR arguments will be used if the size (see the \-s option)
101 is exceeded, unless the \-x option is given, in which case \fBxargs\fR
104 .I "\-\-interactive, \-p"
105 Prompt the user about whether to run each command line and read a line
106 from the terminal. Only run the command line if the response starts
107 with `y' or `Y'. Implies \fI\-t\fR.
109 .I "\-\-no\-run\-if\-empty, \-r"
110 If the standard input does not contain any nonblanks, do not run the
111 command. Normally, the command is run once even if there is no input.
112 This option is a GNU extension.
114 .I "\-\-max\-chars=max-chars, \-s max-chars"
115 Use at most \fImax-chars\fR characters per command line, including the
116 command and initial-arguments and the terminating nulls at the ends of
117 the argument strings. The default is 131072 characters, not including
118 the size of the environment variables (which are provided for
119 separately so that it doesn't matter if your environment variables
120 take up more than 131072 bytes). The operating system places limits
121 on the values that you can usefully specify, and if you exceed these a
122 warning message is printed and the value actually used is set to the
123 appropriate upper or lower limit.
125 .I "\-\-verbose, \-t"
126 Print the command line on the standard error output before executing
130 Print the version number of
135 Exit if the size (see the \fI\-s\fR option) is exceeded.
137 .I "\-\-max\-procs=max-procs, \-P max-procs"
138 Run up to \fImax-procs\fR processes at a time; the default is 1. If
139 \fImax-procs\fR is 0, \fBxargs\fR will run as many processes as
140 possible at a time. Use the \fI\-n\fR option with \fI\-P\fR;
141 otherwise chances are that only one exec will be done.
144 .B find /tmp \-name core \-type f \-print | xargs /bin/rm \-f
149 in or below the directory
151 and delete them. Note that this will work incorrectly if there are
152 any filenames containing newlines or spaces.
154 .B find /tmp \-name core \-type f \-print0 | xargs \-0 /bin/rm \-f
159 in or below the directory
161 and delete them, processing filenames in such a way that file or
162 directory names containing spaces or newlines are correctly handled.
165 .B cut \-d: \-f1 < /etc/passwd | sort | xargs echo
168 Generates a compact listing of all the users on the system.
171 exits with the following status:
174 123 if any invocation of the command exited with status 1-125
175 124 if the command exited with status 255
176 125 if the command is killed by a signal
177 126 if the command cannot be run
178 127 if the command is not found
179 1 if some other error occurred.
182 Exit codes greater than 128 are used by the shell to indicate that
183 a program died due to a fatal signal.
184 .SH "STANDARDS CONFORMANCE"
185 As of GNU xargs version 4.2.9, the default behaviour of
187 is not to have a logical end-of-file marker. POSIX (IEEE Std 1003.1,
188 2004 Edition) allows this.
191 \fBfind\fP(1), \fBlocate\fP(1), \fBlocatedb\fP(5), \fBupdatedb\fP(1),
192 \fBFinding Files\fP (on-line in Info, or printed)
194 The \-L option is incompatible with the \-I option, but should not be.
196 It is not possible for
198 to be used securely, since there will always be a time gap between the
199 production of the list of input files and their use in the commands
202 issues. If other users have access to the system, they can manipulate
203 the filesystem during this time window to force the action of the
206 runs to apply to files that you didn't intend. For a more detailed
207 discussion of this and related problems, please refer to the
208 ``Security Considerations'' chapter in the findutils Texinfo
209 documentation. The -execdir option of
211 can often be used as a more secure alternative.
213 When you use the \-i option, each line read from the input is buffered
214 internally. This means that there is an upper limit on the length
217 will accept when used with the \-i option. To work around this
218 limitation, you can use the \-s option to increase the amount of
221 uses, and you can also use an extra invocation of
223 to ensure that very long lines do not occur.
226 .B somecommand | xargs \-s 50000 echo | xargs \-i \-s 100000 rm '{}'
228 Here, the first invocation of
230 has no input line length limit
231 because it doesn't use the \-i option. The second invocation of
233 does have such a limit, but we have ensured that the it never encounters
234 a line which is longer than it can handle. This is not an ideal
235 solution. Instead, the \-i option should not impose a line length
236 limit, which is why this discussion appears in the BUGS section.
237 The problem doesn't occur with the output of
239 because it emits just one filename per line.
241 The best way to report a bug is to use the form at
242 http://savannah.gnu.org/bugs/?group=findutils.
243 The reason for this is that you will then be able to track progress in
244 fixing the problem. Other comments about \fBxargs\fP(1) and about
245 the findutils package in general can be sent to the
247 mailing list. To join the list, send email to
248 .IR bug\-findutils\-request@gnu.org .