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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Find the package that installed a command

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Copy an element from the previous command
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remove hostname from known_hosts

Sort output by length of line
This provides a way to sort output based on the length of the line, so that shorter lines appear before longer lines. It's an addon to the sort that I've wanted for years, sometimes it's very useful. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

Speed up or slow down video (and audio)
Usage: videospeed video_filename speedchange newfilename videospeed foo.mp4 0.5 foo_slow.mp4 Range of 0.5 (50%) - 2.0 (200%) is valid.

Check a server is up. If it isn't mail me.
For some reason the 2&>1 does not work for me, but the shorter stdout/stderr redirection >& works perfectly (Ubuntu 10.04).

Display _something_ when an X app fails
When you run an X program from a terminal you can see any errors. But when it's run from another X program (eg from a menu item, from your fluxbox 'keys' file etc) it might just die and you see nothing (except perhaps in .xsession-errors). Instead, launch it via this command and you'll see the termination status, stderr and stdout. eg: "xlaunch firefox" or "xlaunch 'echo stdout; echo stderr >&2; false'": 'echo stdout; echo stderr >&2; false' failed with error 1 STDERR: stderr STDOUT: stdout

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


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