Blog – Page 19 – TRUEANGLE

acct for process accounting

ABOUT process accounting

Process accounting is a security method in which an administrator may keep track of system
resources used and their allocation among users, provide for system monitoring, and minimally
track a user's commands. Process accounting has both positive and negative points.

SPECIFIC EXPLANATION
[text]
acct:

highwater lowwater frequency

If BSD-style process accounting is enabled these values control
its behaviour. If free space on filesystem where the log lives
goes below <lowwater>% accounting suspends. If free space gets
above <highwater>% accounting resumes. <Frequency> determines
how often do we check the amount of free space (value is in
seconds). Default:
4 2 30
That is, suspend accounting if there left <= 2% free; resume it
if we got >=4%; consider information about amount of free space
valid for 30 seconds.
[/text]

SHELL SESSION
[bash]
$pwd
/proc/sys/kernel
$cat acct
4 2 30
$su
Password:
root>echo 5 3 40 ? acct
5 3 40 ? acct
root>cat acct
4 2 30
root>echo 5 3 40 > acct
root>cat acct
5 3 40
root>echo 4 2 30 > acct
root>cat acct
4 2 30
root>

[/bash]

LINK
https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
https://www.freebsd.org/doc/handbook/security-accounting.html

ar – create, modify, and extract from archives

ABOUT ar
The archiver, also known simply as ar, is a Unix utility that maintains groups of files as a
single archive file. Today, ar is generally used only to create and update static library files
that the link editor or linker uses and for generating .deb packages for the Debian family; it
can be used to create archives for any purpose, but has been largely replaced by tar for
purposes other than static libraries.[3] An implementation of ar is included as one of the GNU
Binutils.[2]

[bash]
$ar artest.a artest.txt
ar: two different operation options specified
$ar r artest.a artest.txt
ar: creating artest.a
$file artest.a
artest.a: current ar archive
$cat artest.a
!<arch>
artest.txt/ 0 0 0 644 36 `
‘https://youtu.be/-jXqwdd3hk4?t=2418’
$cat artest.txt
‘https://youtu.be/-jXqwdd3hk4?t=2418’

[/bash]

[text]
Single quotes in the shell session are used to hide certain things in wordpress post
They are not part of the real content.
[/text]

LINKS
https://www.geeksforgeeks.org/ar-command-in-linux-with-examples/
https://en.wikipedia.org/wiki/Ar_(Unix)

prayer against depression – by saint ignatius of loyola

O Christ Jesus, when all is darkness and we feel our weakness 
and helplessness, give us the sense of Your presence, Your 
love, and Your strength. Help us to  have perfect trust in
 Your protecting love and strengthening power, so that nothing
may frighten or worry us, for, living close to You, we shall
see Your hand, Your purpose, Your will through all things.

Colossians 3:23-24

23 Whatever you do, do from the heart, as for the Lord and not for others,
24 knowing that you will receive from the Lord the due payment of the inheritance; be slaves of the Lord Christ.

1 PETER 4:8

8 Above all, let your love for one another be intense, because love covers a multitude of sins.

PROVERBS 18:16

16 Gifts clear the way for people, winning access to the great.

HEBREW 5:8-9

8 Son though he was, he learned obedience from what he suffered;
9 and when he was made perfect, he became the source of eternal salvation for all who obey him,

Fundamental related of a bash builtin command named “if”

ABOUT if

Conditionals have many forms. The most basic form is: if expression then statement where
'statement' is only executed if 'expression' evaluates to true. '21' evaluates to true.xs

TYPICAL SHELL EXPOSURE
[bash]
$if true; then echo "works" ; fi
works
$if false; then echo "works" ; fi
$
[/bash]

LINK
https://stackoverflow.com/questions/16034749/if-elif-else-statement-issues-in-bash
http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO-6.html

Fundamental of a bash builtin command named “unalias”

ABOUT unalias

Remove each name from the list of defined aliases.  If -a is supplied, all alias definitions
are removed.  The return  value  is true unless a supplied name is not a defined alias.

[bash]
$unalias
unalias: usage: unalias [-a] name [name …]
$echo $?
2
$unalias -a
$echo $?
0
$unalias pwd
bash: unalias: pwd: not found
$pwd
/home/jeffrin
$alias ls list
bash: alias: ls: not found
bash: alias: list: not found
$alias list ls
bash: alias: list: not found
bash: alias: ls: not found
$alias pwd pwf
bash: alias: pwd: not found
bash: alias: pwf: not found
$alias
$alias list="ls"
$unalias list
$echo $?
0
$list
bash: list: command not found
$

[/bash]

LINK
https://www.quora.com/What-is-the-alias-unalias-command-in-Unix

Simple example of a bash builtin command named “wait”

ABOUT wait

wait waits for the process identified by process ID pid (or the job specified by job ID jobid), and
reports its termination status. If an ID is not given, wait waits for all currently active child
processes, and the return status is zero. If the ID is a job specification, wait waits for all processes
in the job's pipeline.

A TYPICAL SHELL EXPOSURE
[bash]
$sleep 10 &
[1] 7122
$wait 7122
[1]+ Done sleep 10
$sleep 20 &
[1] 7125
$wait 7125
[1]+ Done sleep 20
$sleep 20 &
[1] 7128
$wait 7128
[1]+ Done sleep 20
$sleep 20 &
[1] 7135
$wait 7135
[1]+ Done sleep 20
$wait
$wait
$

[/bash]

LINK
https://www.computerhope.com/unix/uwait.htm