How to create a compressed file trace



October 2003

Often, it is necessary to get a file trace of a lengthy program, and the file can get rather large. Usually, the size of the trace file can be controlled by using the configuration variable MAX_ERROR_LINES. Sometimes, however, a full trace file is needed. Here is an easy way to get a compressed file trace on UNIX. By using Gzip, you should be able to get about 97% compression on a level 8 file trace file.

  1. Create a named pipe (FIFO) somewhere convenient:
    $ mknod file-trace p
    
  2. Run your compression program, using the named pipe as input, and redirecting the compressed output to another file:
    $ gzip -9v < file-trace > file-trace.gz
    
  3. This command will wait until the runtime closes the file trace file. Then, from another shell, run your runtime, directing the error file to the FIFO:
    $ runcbl -lex file-trace program.acu
    

After the program exits, the gzip will finish and the error file contents will be gzipped up in file-trace.gz.

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