Check These Out
A common mistake in Bash is to write command-line where there's command a reading a file and whose result is redirected to that file.
It can be easily avoided because of :
1) warnings "-bash: file.txt: cannot overwrite existing file"
2) options (often "-i") that let the command directly modify the file
but I like to have that small function that does the trick by waiting for the first command to end before trying to write into the file.
Lots of things could probably done in a better way, if you know one...
This is a beginning script. You can create a file with > filename. You can also use diff to compare output run at different times to verify no change in your files. I apologize in advance if this is too simple. For some it should be a start.
My version uses printf and command substitution ($()) instead of echo -e and xargs, this is a few less chars, but not real substantive difference.
Also supports lowercase hex letters and a backslash (\) will make it through unescaped
Someone might attack on your system. You can drop attacker IP using IPtables. However, you can use route command to null route unwanted traffic. A null route (also called as blackhole route) is a network route or kernel routing table entry that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall. The act of using null routes is often called blackhole filtering.
Installs pip packages defining a proxy
Sometimes commands give you too much feedback.
Perhaps 1/100th might be enough. If so, every() is for you.
$ my_verbose_command | every 100
will print every 100th line of output.
Specifically, it will print lines 100, 200, 300, etc
If you use a negative argument it will print the *first* of a block,
$ my_verbose_command | every -100
It will print lines 1, 101, 201, 301, etc
The function wraps up this useful sed snippet:
$ ... | sed -n '0~100p'
don't print anything by default
$ sed -n
starting at line 0, then every hundred lines ( ~100 ) print.
$ '0~100p'
There's also some bash magic to test if the number is negative:
we want character 0, length 1, of variable N.
$ ${N:0:1}
If it *is* negative, strip off the first character ${N:1} is character 1 onwards (second actual character).
This command converts filenames with embedded spaces in the current directory replacing spaces with the underscore ("_") character.
Not sure if it works the same on any shell.
