Commands tagged parameter expansion (7)

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merge vob files to mpg

check open ports without netstat or lsof

Find the package that installed a command

Print random emoji in terminal
This will print a random emoji within the range of 1F600 - 1F64F, which includes all the face emoji. Obviously, this will only show something meaningful if your terminal can display emoji, but it may be useful in scripts. This likely requires recent versions of bash

Create a directory and change into it at the same time
How often do you make a directory (or series of directories) and then change into it to do whatever? 99% of the time that is what I do. This BASH function 'md' will make the directory path then immediately change to the new directory. By using the 'mkdir -p' switch, the intermediate directories are created as well if they do not exist.

Convert text to picture
generates a picture file with the text. Some other samples in: http://www.imagemagick.org/Usage/text/

Most simple way to get a list of open ports

Count files beneath current directory (including subfolders)

sed : using colons as separators instead of forward slashes
Having to escape forwardslashes when using sed can be a pain. However, it's possible to instead of using / as the separator to use : . I found this by trying to substitute $PWD into my pattern, like so $ sed "s/~.*/$PWD/" file.txt Of course, $PWD will expand to a character string that begins with a / , which will make sed spit out an error such as "sed: -e expression #1, char 8: unknown option to `s'". So simply changing it to $ sed "s:~.*:$PWD:" file.txt did the trick.

list file descriptors opened by a process
Useful for examining hostile processes (backdoors,proxies)


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