Execute utility, passing constructed argument list(s).
Read space, tab, newline and end-of-file delimited arguments from standard input and execute the specified utility with them as arguments. The arguments are typically a long list of filenames (generated by ls or find, for example) that get passed to xargs via a pipe.
Syntax xargs [-0pt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr] [-L number] [-n number [-x]] [-P maxprocs] [-s size] [utility [argument ...]] If no utility is specified, echo is used. Key -0 Change xargs to expect NUL (`\0') characters as separators, instead of spaces and newlines. This is expected to be used in concert with the -print0 function in find. -E eofstr Use eofstr as a logical EOF marker. -I replstr Execute utility for each input line, replacing one or more occurences of replstr in up to replacements (or 5 if no -R flag is specified) arguments to utility with the entire line of input. The resulting arguments, after replacement is done, will not be allowed to grow beyond 255 bytes; this is implemented by concate- nating as much of the argument containing replstr as possible, to the constructed arguments to utility, up to 255 bytes. The 255 byte limit does not apply to arguments to utility which do not contain replstr, and furthermore, no replacement will be done on utility itself. Implies -x. -J replstr If this option is specified, xargs will use the data read from standard input to replace the first occurrence of replstr instead of appending that data after all other arguments. This option will not effect how many arguments will be read from input (-n), or the size of the command(s) xargs will generate (-s). The option just moves where those arguments will be placed in the command(s) that are executed. The replstr must show up as a dis- tinct argument to xargs. It will not be recognized if, for instance, it is in the middle of a quoted string. Furthermore, only the first occurrence of the replstr will be replaced. For example, the following command will copy the list of files and directories which start with an uppercase letter in the current directory to destdir: /bin/ls -1d [A-Z]* | xargs -J % cp -rp % destdir -L number Call utility for every number lines read. If EOF is reached and fewer lines have been read than number then utility will be called with the available lines. -n number Set the maximum number of arguments taken from standard input for each invocation of the utility. An invocation of utility will use less than number standard input arguments if the number of bytes accumulated (see the -s option) exceeds the specified size or there are fewer than number arguments remaining for the last invocation of utility. The current default value for number is 5000. -o Reopen stdin as /dev/tty in the child process before executing the command. This is useful if you want xargs to run an interactive application. -P maxprocs Parallel mode: run at most maxprocs invocations of utility at once. -p Echo each command to be executed and ask the user whether it should be executed. An affirmative response, `y' in the POSIX locale, causes the command to be executed, any other response causes it to be skipped. No commands are executed if the process is not attached to a terminal -R replacements Specify the maximum number of arguments that -I will do replacement in. -s size Set the maximum number of bytes for the command line length pro- vided to utility. The sum of the length of the utility name, the arguments passed to utility (including NULL terminators) and the current environment will be less than or equal to this number. The current default value for size is ARG_MAX - 4096. -t Echo the command to be executed to standard error immediately before it is executed. -x Force xargs to terminate immediately if a command line containing number arguments will not fit in the specified (or default) command line length.
The utility and any arguments specified on the command line are given to the utility upon each invocation, followed by some number of the arguments read from standard input. The utility is repeatedly executed until standard input is exhausted.
Spaces, tabs and newlines may be embedded in arguments using single ( ' ) or double ( " ) quotes or backslashes ( \ ). Single quotes escape all non-single quote characters, excluding newlines, up to the matching single quote. Double quotes escape all non-double quote characters, excluding newlines, up to the matching double quote. Any single character, including newlines, may be escaped by a backslash.
Undefined behavior may occur if utility reads from the standard input.
The xargs utility exits immediately (without processing any further input) if a command line cannot be assembled, utility cannot be invoked, an invocation of the utility is terminated by a signal or an invocation of the utility exits with a value of 255.
xargs exits with a value of 0 if no error occurs.
If utility cannot be found, xargs exits with a value of 127, otherwise if utility cannot be executed, xargs exits with a value of 126. If any other error occurs, xargs exits with a value of 1.
Touch all the files in the current directory (.) to be dated 31st December (12 31) at 09.30, -print0 is required if any filenames contain whitespace.
$ find . -print0 | xargs -0 touch -t 12310930
Find and delete all files in the /work folder which have been modified in the last 30 minutes:
$ find ./work -mmin -30 | xargs -0 rm
Read a list of filenames from filelist.txt (one per line) and copy them to new_folder:
$ cat filelist.txt | xargs -J % cp % new_folder
“Discovery consists of seeing what everybody has seen and thinking what nobody has thought” ~ Albert Szent-Gyorgyi
Related macOS commands:
echo - Display message on screen.
env - Set environment and run a utility
find - Search for files that meet a desired criteria