Commands by alcik (4)

  • You can use wildcard with rpm search but you have to do 2 things: 1. use "-a" switch (means "all") with query ("-q") switch - argument is a pattern to use while searching for package names of all installed packages 2. protect wildcards, so that shell could not eat them - escape it with backslash ("\") or enclose all pattern between apostrophes ("'"): rpm -qa 'co*de' As you can see above it is possible to insert wildcards into middle of the pattern. If you want, you can add "-i" or another rpm query options, "-i" will print package information for all installed packages matching pattern. Show Sample Output


    2
    rpm -qa \*code\*
    alcik · 2009-03-11 21:16:23 1
  • This example summarize size of all pdf files in /tmp directory and its subdirectories (in bytes). Replace "/tmp" with directory path of your choice and "\*pdf" or even "-iname \*pdf" with your own pattern to match specific type of files. You can replace also parameter for du to count kilo or megabytes, but because of du rounding the sum will not be correct (especially with lot of small files and megabytes counting). In some cases you could probably use sth like this: du -cb `find /tmp -type f -iname \*pdf`|tail -n 1 But be aware that this second command CANNOT count files with spaces in their names and it will cheat you, if there are some files matching the pattern that you don't have rights to read. The first oneliner is resistant to such problems (it will not count sizes of files which you cant read but will give you correct sum of rest of them). Show Sample Output


    0
    SUM=0; for FILESIZE in `find /tmp -type f -iname \*pdf -exec du -b {} \; 2>/dev/null | cut -f1` ; do (( SUM += $FILESIZE )) ; done ; echo "sum=$SUM"
    alcik · 2009-03-05 17:16:52 3
  • It displays, last 15 yum operations (in last operation as first row order) with its dates. Change 15 to any number of operations you need to display or remove "| tac" to see it in reverse order (last operation as last row)


    0
    tail -n 15 /var/log/yum.log | tac
    alcik · 2009-03-02 08:56:04 1
  • Replace 'more' command with any command which is in your PATH. Show Sample Output


    3
    rpm -qif `which more`
    alcik · 2009-02-27 08:59:07 2

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Output a SSL certificate start or end date
A quick and simple way of outputting the start and end date of a certificate, you can simply use 'openssl x509 -in xxxxxx.crt -noout -enddate' to output the end date (ex. notAfter=Feb 01 11:30:32 2009 GMT) and with the date command you format the output to an ISO format. For the start date use the switch -startdate and for end date use -enddate.

disable caps lock
a quick one-line way to disable caps lock while running X.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Check wireless link quality with dialog box
The variable WIRELESSINTERFACE indicates your wireless interface

Colorized JSON pretty printing
Uses pygmentize and python to create indented and colorized JSON output

bash shell expansion
The expansion {,} in bash will repeat the given string once for each item seperated by commas. The given command will result in the following being run: cp /really/long/path/and/file/name /really/long/path/and/file/name-`date -I` These can be embedded as needed, ex: rm file{1,2,3{1,2,3}} would delete the files file1, file2, file31, file32, file32, and no other files.

Create multiple mp4 files using avidemux
Convert multiple files using avidemux. Version updated (thanks to the guys who helped me giving me hints about how to improve the command). Works with files whose name contains blank characters. One of the reasons why I love open source: everyone can take something "done" and improve it to make it better! If u have suggestions, please let me know.

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Print a row of 50 hyphens
This feels more intuitive to me.


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