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Bash functions to list and kill or send signals to process trees

Posted 03-31-2012 at 11:54 PM by konsolebox
Updated 06-14-2015 at 08:54 AM by konsolebox

These functions can be used in scripts or interactive shells to manipulate process trees. At least bash version 3.0 is needed. May also work with some earlier versions.

kill_tree - Creates a list of processes based from a parent process ID first then sends the signal to all of them synchronously.

kill_tree_2 - Same as killtree but it doesn't create a list first. It immediately kills processes as it goes through every level.

kill_tree_3 - This version...
Senior Member
Posted in Howtos
Views 2662 Comments 0 konsolebox is offline

Handling all file names safely in Bash

Posted 02-11-2012 at 12:09 PM by Nominal Animal
Updated 04-16-2012 at 02:41 AM by Nominal Animal (Fuller fixes.)
Tags bash, filename, nul

In Linux, each file or directory name (or more generally, pathname component) is just a string of bytes. It always ends with the C end-of-string mark, ASCII NUL: a zero. Value 47, ASCII /, is also reserved for use as a separator between pathnames.

Bash can read ASCII NUL separated data using read -d "" variable. It will, however, remove leading and trailing characters that match IFS, and return false (nonzero status) if the input does not have a final NUL. This applies to...
Senior Member
Posted in Uncategorized
Views 1546 Comments 0 Nominal Animal is offline

Bash scripts and keyboard input

Posted 01-29-2012 at 02:43 PM by Nominal Animal

You can use Bash to read individual keypresses. Here is an example:

# Reset terminal to current state when we exit.
trap "stty $(stty -g)" EXIT

# Disable echo and special characters, set input timeout to 0.2 seconds.
stty -echo -icanon time 2 || exit $?

# String containing all keypresses.

# Set field separator to BEL (should not occur in keypresses)
Senior Member
Posted in Uncategorized
Views 7619 Comments 0 Nominal Animal is offline

Slacking with Slackware

Posted 12-01-2011 at 08:11 AM by ofaring (Debian, This That and the Other)
Updated 12-01-2011 at 08:14 AM by ofaring

Ok. I've used Debian for quite some time -- although I started with Slackware years back -- and it's been awhile since I attempted anything without a package manager!

I grabbed a copy of Slackware Disc 1 and installed a basic, console-only Slackware.

First snag...WiFi. I live in a busy neighbourhood full of students eager to grab "free" internet off a WEP-encrypted wireless router, so WPA is a must. Well, /etc/rc.d/rc.inet1.conf didn't seem very happy to play...
Posted in Examples, Slackware
Views 1032 Comments 0 ofaring is offline

Comment a block in shell

Posted 08-31-2011 at 12:22 AM by hi2arun
Tags bash, script

We all know, to comment out a line in shell script, '#' token is inserted in the line that needs to be made dead.

# This is a dead line
echo "This line is live"
However, '#' token can be pesky if a block of lines need to be commented out.
Say, to comment out the following block using '#'

# comment starts here
# All these lines
# are blocked
# using '#' token
# ...
# ...
# ...
Posted in Uncategorized
Views 891 Comments 0 hi2arun is offline


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