Hacker News Reader

Comment by cperciva | Hacker News Reader

Your approach works better than backtick expansion, since it won't run into 'command line too long' issues; but it will still break on "weird" file names (e.g., file names with spaces in them). The correct way to do this is

    find . -name *.java -print0 | xargs -0 cat | wc -l

View on HN

BTW, recent versions of linux don't have a fixed limit on command line length.

The command line can be a large as available memory (for a single processes). (Although the ratio between command line length and allocated memory is not obvious since it depends on the number of words in the command line.)

That glob could cause trouble.

    find . -name '*.java' -print0 | xargs -0 cat | wc -l

xargs can still run you into the 'too many args' issue. You'll want to use this:

       --max-args=max-args
       -n max-args
              Use  at  most max-args arguments per command
              line.  Fewer than max-args arguments will be used
              if the size (see the -s option) is exceeded,
              unless the -x option is given, in which case xargs
              will exit.

Only if there's a bug in your xargs. POSIX states:

The xargs utility shall limit the command line length such that when the command line is invoked, the combined argument and environment lists (see the exec family of functions in the System Interfaces volume of POSIX.1-2008) shall not exceed {ARG_MAX}-2048 bytes

so you should never run into the ARG_MAX limit.

Reply on news.ycombinator.com