1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" John B. Roll Jr. and the Institute of Electrical and Electronics 6.\" Engineers, Inc. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)xargs.1 8.1 (Berkeley) 6/6/93 37.\" $FreeBSD$ 38.\" 39.Dd May 7, 2001 40.Dt XARGS 1 41.Os 42.Sh NAME 43.Nm xargs 44.Nd "construct argument list(s) and execute utility" 45.Sh SYNOPSIS 46.Nm 47.Op Fl 0 48.Op Fl J Ar replstr 49.Oo 50.Fl n Ar number 51.Op Fl x 52.Oc 53.Op Fl s Ar size 54.Op Fl t 55.Op Ar utility Op Ar argument ... 56.Sh DESCRIPTION 57The 58.Nm 59utility reads space, tab, newline and end-of-file delimited arguments 60from the standard input and executes the specified 61.Ar utility 62with them as 63arguments. 64.Pp 65The utility and any arguments specified on the command line are given 66to the 67.Ar utility 68upon each invocation, followed by some number of the arguments read 69from standard input. 70The 71.Ar utility 72is repeatedly executed until standard input is exhausted. 73.Pp 74Spaces, tabs and newlines may be embedded in arguments using single 75(``\ '\ '') 76or double (``"'') quotes or backslashes (``\e''). 77Single quotes escape all non-single quote characters, excluding newlines, 78up to the matching single quote. 79Double quotes escape all non-double quote characters, excluding newlines, 80up to the matching double quote. 81Any single character, including newlines, may be escaped by a backslash. 82.Pp 83The options are as follows: 84.Bl -tag -width indent 85.It Fl 0 86Change 87.Nm 88to expect NUL 89(``\\0'') 90characters as separators, instead of spaces and newlines. 91This is expected to be used in concert with the 92.Fl print0 93function in 94.Xr find 1 . 95.It Fl J Ar replstr 96If this option is specified, 97.Nm 98will use the data read from standard input to replace the first occurrence of 99.Ar replstr 100instead of appending that data after all other arguments. 101This option will not effect how many arguments will be read from input 102.Pq Fl n , 103or the size of the command(s) 104.Nm 105will generate 106.Pq Fl s . 107The option just moves where those arguments will be placed in the command(s) 108that are executed. 109The 110.Ar replstr 111must show up as a distinct 112.Ar argument 113to 114.Nm . 115It will not be recognized if, for instance, it is in the middle of a 116quoted string. 117Furthermore, only the first occurrence of the 118.Ar replstr 119will be replaced. 120For example, the following command will copy the list of files and 121directories which start with an uppercase letter in the current 122directory to 123.Pa destdir : 124.Pp 125.Dl /bin/ls -1d [A-Z]* | xargs -J [] cp -rp [] destdir 126.Pp 127.It Fl n Ar number 128Set the maximum number of arguments taken from standard input for each 129invocation of the utility. 130An invocation of 131.Ar utility 132will use less than 133.Ar number 134standard input arguments if the number of bytes accumulated (see the 135.Fl s 136option) exceeds the specified 137.Ar size 138or there are fewer than 139.Ar number 140arguments remaining for the last invocation of 141.Ar utility . 142The current default value for 143.Ar number 144is 5000. 145.It Fl s Ar size 146Set the maximum number of bytes for the command line length provided to 147.Ar utility . 148The sum of the length of the utility name, the arguments passed to 149.Ar utility 150(including 151.Dv NULL 152terminators) and the current environment will be less than or equal to 153this number. 154The current default value for 155.Ar size 156is 157.Dv ARG_MAX 158- 4096. 159.It Fl t 160Echo the command to be executed to standard error immediately before it 161is executed. 162.It Fl x 163Force 164.Nm 165to terminate immediately if a command line containing 166.Ar number 167arguments will not fit in the specified (or default) command line length. 168.El 169.Pp 170If no 171.Ar utility 172is specified, 173.Xr echo 1 174is used. 175.Pp 176Undefined behavior may occur if 177.Ar utility 178reads from the standard input. 179.Pp 180The 181.Nm 182utility exits immediately (without processing any further input) if a 183command line cannot be assembled, 184.Ar utility 185cannot be invoked, an invocation of the utility is terminated by a signal 186or an invocation of the utility exits with a value of 255. 187.Pp 188The 189.Nm 190utility exits with a value of 0 if no error occurs. 191If 192.Ar utility 193cannot be invoked, 194.Nm 195exits with a value of 127. 196If any other error occurs, 197.Nm 198exits with a value of 1. 199.Sh SEE ALSO 200.Xr echo 1 , 201.Xr find 1 , 202.Xr execvp 3 203.Sh STANDARDS 204The 205.Nm 206utility is expected to be 207.St -p1003.2 208compliant. 209The 210.Fl J 211option is a non-standard 212.Fx 213extension which may not be available on other operating systems. 214.Sh BUGS 215If 216.Ar utility 217attempts to invoke another command such that the number of arguments or the 218size of the environment is increased, it risks 219.Xr execvp 3 220failing with 221.Er E2BIG . 222