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05-E.8.2: File Output Manipulation - xargs

  • Page ID
    32560
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    The xargs Command

    xargs is a Unix command which can be used to build and execute commands from standard input.

    Importance :
    Some commands like grep can accept input as parameters, but some commands accepts arguments. This is where xargs came into the picture.

    Syntax :

    xargs [ OPTIONS ] [command]

    xargs Command Options

    Options Option Meaning
    0 Input items are terminated by null character instead of white spaces.
    -a file Read items from file instead of standard input.
    –delimiter = delim Input items are terminated by a special character.
    -E eof-str Set the end of file string to eof-str.
    -I replace-str Replace occurrences of replace-str in the initial arguments with names read from standard input.
    -L max-lines Use at-most max-lines non-blank input lines per command line.
    -p Prompt the user about whether to run each command line and read a line from terminal.
    -r If the standard input does not contain any nonblanks, do not run the command.
    -x Exit if the size is exceeded.
    –help Print the summary of options to xargs and exit.
    –version Print the version no. of xargs and exit.

    Simply put xargs takes each input and applies the command to that input. Below are some examples of xargs:

    # the file states.list contains 3 names, we cat the file and pipe the output to xargs mkdir - xargs 
    # takes each line from the file and uses it as an argument to mkdir
    pbmac@pbmac-server $ cat states.list 
    Alabama
    Wyoming
    Washington
    pbmac@pbmac-server $ cat states.list | xargs mkdir
    pbmac@pbmac-server $ ls
    Alabama  states.list  Washington  Wyoming
    
    # now we use find, searching for type d (directory) and send all the output to xargs rmdir
    # the error message is becasue the find command also finds the . directory - the directory where we currently are
    pbmac@pbmac-server $ find . -type d | xargs rmdir
    rmdir: failed to remove '.': Invalid argument
    pbmac@pbmac-server $ ls
    pbmac@pbmac-server $
    
    # there are 3 files ending in .txt, using the find command we pipe the output of the find to xzargs rm to remove
    # each .txt file.
    pbmac@pbmac-server $ ls
    one.txt  states.list  three.txt  two.txt
    pbmac@pbmac-server $ find . -name "*.txt" | xargs rm
    pbmac@pbmac-server $ ls
    states.list
    

    Adapted from:
    "xargs command in Linux with examples" by Mandeep Singh, Geeks for Geeks is licensed under CC BY-SA 4.0


    05-E.8.2: File Output Manipulation - xargs is shared under a CC BY-NC license and was authored, remixed, and/or curated by LibreTexts.

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