Commands by RAKK (5)

  • Lists directory size up to a maximum traversal depth on systems like IBM AIX, where the du command doesn't have Linux's --max-depth option. AIX's du uses -g to display directory size on gigabytes, -m to use megabytes, and -k to use kilobytes. tr### is a Perl function that replaces characters and returns the amount of changed characters, so in this case it will return how many slashes there were in the full path name. Show Sample Output


    0
    du -g | perl -ne 'print if (tr#/#/# == <maximum depth>)'
    RAKK · 2014-02-15 07:33:36 0
  • This command allows you to mirror folders or files with rsync using a secure SSH channel with a forced HMAC integrity algorithm. Use this if you are absolutely adamant about preserving data integrity while mirroring a set of files. --partial is for resumability.


    0
    rsync -av -e "ssh -o MACs=hmac-ripemd160" --progress --partial user@remotehost://path/to/remote/stuff .
    RAKK · 2014-02-01 00:46:38 0
  • This command is used to verify a sha256sum-formatted file hash list on IBM AIX or any other UNIX-like OS that has openssl but doesn't have sha256sum by default. Steps: 1: Save to the filesystem a script that: A: Receives as arguments the two parts of one line of a sha256sum listing B: Feeds a file into openssl on SHA256 standard input hash calculation mode, and saves the result C: Compares the calculated hash against the one received as argument D: Outputs the result in a sha256sum-like format 2: Make the script runnable 3: Feed the sha256sum listing to xargs, running the aforementioned script and passing 2 arguments at a time Show Sample Output


    0
    echo '#! /usr/bin/ksh\ncat $2 | openssl dgst -sha256 | read hashish; if [[ $hashish = $1 ]]; then echo $2: OK; else echo $2: FAILED; fi;' > shacheck; chmod +x shacheck; cat hashishes.sha256 | xargs -n 2 ./shacheck;
    RAKK · 2013-09-18 21:51:20 2
  • This command is for UNIX OSes that have plain vanilla System V UNIX commands instead of their more functional GNU counterparts, such as IBM AIX.


    1
    gzip -cd gzippedarchive.tar.gz | tar -xf -
    RAKK · 2013-09-18 17:41:25 0
  • This command is for producing GNU sha256sum-compatible hashes on UNIX systems that don't have sha256sum but do have OpenSSL, such as stock IBM AIX. 1.- Saves a wrapper script for UNIX find that does the following: A.- Feeds a file to openssl on SHA256 hash calculation mode B.- Echoes the output followed by the filename 2.- Makes the file executable 3.- Runs find on a directory, only processing files, and running on each one the wrapper script that calculates SHA256 hashes Pending is figuring out how to verify a sha256sum file on a similar environment. Show Sample Output


    0
    echo '#! /usr/bin/ksh\necho `cat $1 | openssl dgst -sha256` $1' > sslsha256; chmod +x sslsha256; find directory -type f -exec ./sslsha256 \{\} \;
    RAKK · 2013-09-18 17:37:50 0

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Move a folder and merge it with another folder
This will move a folder and merge it with another folder which may contain duplicates. Technically it's just creating hardlinks of everything in the folder, and after it's done, delete the source (with rm -r source/ ) to complete the move. This is much faster than, for example, using rsync to merge folders which would actually copy the entire contents and so for a lot of files would take much longer. This uses macutils gcp port of cp so it can be used on osx/MacOS. If using in linux or some unix where cp includes the ability to create links with -l you can just use cp instead of gcp.

Go to the next sibling directory in alphabetical order
Sometimes you have to browse your way through a lot of sub-directories. This command cd to the next sub-directory in alphabetical order. For example, if you have the directories "lectures/01-intro", "lectures/02-basic", "lectures/03-advanced" and so on, and your PWD is "02-basic", it jumps to "03-advanced".

List of macros defined by gcc
Lists all macros and their values defined by gcc.

check open ports without netstat or lsof

list block devices
Shows all block devices in a tree with descruptions of what they are.

Compare directories via diff
http://hints.macworld.com/article.php?story=20070408062023352

list all file extensions in a directory
If your grep doesn't have an -o option, you can use sed instead.

determine if tcp port is open
@putnamhill, no need if statement in that case. && is a AND and || is a OR


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