Bash Index : I - Httqm's Docs

Command line system information script for console and IRC

In order to maintain basic privacy and security, inxi used on IRC automatically filters out your network device MAC address, WAN and LAN IP, your /home username directory in partitions, and a few other items.

Flag	Usage
-A --audio
-b --basic
-B --battery
-c --color	disable colors with -c 0
-C --cpu
-G --graphics	-Gx, -Gxx, -Gxxx for increased verbosity
-L --logical	show logical volume information, for LVM, LUKS, bcache, etc
-m --memory
-M --machine	show machine data : device motherboard BIOS and if present : system builder (such as Lenovo)
-N --network
-S --system
-J --usb

show information on IPC facilities

Flag	Usage
-a --all	show information about all 3 sources (default) : shared memory segments queues semaphores
-c --creator	show creator and owner
--human	print sizes in human-readable format
-l --limit	show resource limits
-m --shmems	show information about shared memory segments
-p --pid	show PIDs of creator (in cpid column) and last operator (in lpid column)
-q --queues	show information about active message queues
-s --semaphores	show information about active semaphores sets

example 1

ipcs -p m

------ Shared Memory Creator/Last-op PIDs --------
shmid		owner	cpid	lpid
8945664		root	4974	18423
8716295	root	1289	1289
8749064		apache	1289	18423
8781833		apache	1289	18423
8814602		apache	1289	18423
8847371		apache	1289	18423
8880140		apache	1289	18423
8912909		apache	1289	18423

ps 1289
```
(nothing)
```
The process 1289 initiated a shared memory segment, was the last process to operate on this memory segment, but it's dead now. Looks like a memory leak.
Let's remove it :
ipcrm -m 8716295

install = mkdir -p + chown + chmod

Copy files while setting their file mode (aka permission) bits and, if possible, their owner and group.

Even though you have no freshly-compiled software to install, install is very convenient to do things like :

mkdir -p /path/to/my/dir && chown bob:developers /path/to/my/dir && chmod 700 /path/to/my/dir

with a single command :

install -d /path/to/my/dir -o bob -g developers -m 700

Flag	Usage
-d some/directory --directory some/directory	create missing parent directories (if any), giving them default attributes (755 permissions) create each given directory set owner + group + mode as specified (or use defaults : current user (the man says "root") + current user's group + `u=rwx,go=rx,a-s`)
-g group --group group	set the group ownership of installed files or directories to group
-m mode --mode mode	set the file mode bits for the installed file or directory to mode, which can be either an octal number (700) or a symbolic mode (u=rwx,go=) as in chmod
-o user --owner user	set the ownership of installed files or directories to user

inotify-tools

Wait for changes to files using inotify

Flag	Usage
-m --monitor	Instead of exiting after receiving a single event, execute indefinitely
--format formatSpec	Output in a user-specified format, using printf-like syntax : `%e` : comma-separated list of the event(s) that occurred `%Xe` : like `%e` with X instead of a comma `%f` : name of the file affected by the event

Experimenting with inotifywait :

inotifywait -m --format 'EVENT: "%:e", FILE: "%f"' . &

[1] 15730
Setting up watches.
Watches established.

touch newFile

EVENT: "CREATE", FILE: "newFile"
EVENT: "OPEN", FILE: "newFile"
EVENT: "ATTRIB", FILE: "newFile"
EVENT: "CLOSE_WRITE:CLOSE", FILE: "newFile"

echo hello > newFile

EVENT: "MODIFY", FILE: "newFile"
EVENT: "OPEN", FILE: "newFile"
EVENT: "MODIFY", FILE: "newFile"
EVENT: "CLOSE_WRITE:CLOSE", FILE: "newFile"

echo world >> newFile

EVENT: "OPEN", FILE: "newFile"
EVENT: "MODIFY", FILE: "newFile"
EVENT: "CLOSE_WRITE:CLOSE", FILE: "newFile"

rm newFile

EVENT: "DELETE", FILE: "newFile"

fg

CTRL-c

Alternate solution to detect the creation of a file :

#!/usr/bin/env bash

fileToWatch='path/to/some/file'
[ -f "$fileToWatch" ] && rm "$fileToWatch"
while true; do
	[ -f "$fileToWatch" ] && { echo 'file created'; exit; }
done

Set / display a process I/O nice value.

Flag	Usage
-c classValue	Apply the specified class value to the process. Class values : 0 : none 1 : real time 2 : best-effort. This is the effective scheduling class for any process that has not asked for a specific I/O priority. This class takes a priority argument 3 : idle. Get disk time when no other program has asked for disk I/O for a defined grace period. Impact on normal system activity should be zero.
-n priority	Priority of job within its class. Ranges from 0 (highest) to 7 (lowest).
-p PID	Apply to the specified process ID

root permissions are required to :

raise anything to real time class
change class on another process (use of -p), even if you're lowering your own processes to idle

Set the ionice value of the process having the PID 9799

ionice -c 3 -p 9799

Display the ionice value of the process having the PID 9799

ionice -p 9799

Set the actual shell to idle priority :

This is useful when you don't want local shell actions to interfere with existing processes : ionice -c3 -p$$

iftop is not really a Bash command, it's an additional utility designed to monitor network usage.
It can easily be installed on "Debianoids" with apt-get install iftop.
Running iftop requires root privileges.

Flag	Usage
-i interface	Listen on interface

Monitor usage of interface eth0 :

iftop -i eth0

interactive-mode keys :

Flag	Usage
?	show help

Start an innotop session :

innotop -h host -u login -ppassword

Report CPU and I/O stats :

iostat options interval/count

This comes from the sysstat Debian package.

Flag	Usage
-c	display the CPU usage report
-d	display the device usage report
-h	make the NFS report human-readable
-m	display statistics in megabytes per second instead of blocks or kilobytes per second
-n	display the network filesystem (NFS) report
-x	display extended statistics

NFS report updated every 2 seconds :

iostat -nhm 2

print real and effective user and group IDs
If no username is provided, id returns information about the user invoking it.

Special uid's

root has the uid 0
nobody has the largest possible uid (as the opposite of the superuser) : 32767

Flag	Usage
-u --user	print only the effective user ID
-n --name	print a name instead of a number If you need to get the current user name : id -un will do the trick $USER is even simpler

Show / manipulate routing, devices, policy routing and tunnels.

Synopsis :

ip options object command

Objects :

link :
addr
addrlabel
route
rule
neigh
tunnel
maddr
mroute
monitor

ip link :

Get interface status (name + up/down status + MTU + MAC address) :

ip link show
ip link show eth0

Turn interface up/down :

~~ifconfig lo up|down~~

ip link set lo up|down

ip addr :

Get interface status :

ip addr
ip a
ip addr show eth0
ip a s eth0

Assign IP address to interface :

ip addr add ipAddress/maskLength dev device

Create a virtual interface :

deviceName='eth0:test'; ipAddress='192.168.1.42'; maskLength=24; ip addr add $ipAddress/$maskLength dev $deviceName; ip a s $deviceName; ping -c 3 $ipAddress; ip addr del $ipAddress/$maskLength dev $deviceName; ip a

ip route :

show (list) routes :

ip route
ip route show

add a route (source) :

ip route add network/mask via gatewayIp
ip route add network/mask dev device

delete a route :

ip route del routeSpecification

The man page says routeSpecification has the same format than for ip route add (see example). So replaying the ip route add ... command replacing add with del should do the job .

find the network gateway (i.e. router)'s IP address :

ip r | grep default

default via 192.168.105.254 dev eth0 proto static metric 100

find the route that will be used to reach the specified IP address : ip route get 8.8.8.8 short version : ip r g 8.8.8.8

8.8.8.8 via 10.0.2.2 dev eth0 src 10.0.2.15
	cache

ip rule (source) :

This is the command to manipulate the RPDB.

iotop

top-like I/O monitor

Flag	Usage
-a --accumulated	Show accumulated I/O instead of bandwidth. In this mode, iotop shows the amount of I/O processes have done since iotop started.
-b --batch	Turn on non-interactive mode. Useful for logging I/O usage over time.
-d seconds --delay=seconds	Set the delay between iterations in seconds (1 second by default). Accepts non-integer values such as 1.1 seconds.
-o --only	Show only processes doing I/O instead of showing them all. Can be toggled dynamically by pressing o.
-P --processes	Show only processes (processes + threads by default)
-p PIDs --pid=PIDs	Monitor PIDs (all by default)
-u users --user=users	Monitor processes from the users list (all by default)

How to find which process is regularly writing to disk? (source)

Every 10 secs, print a list of processes that read/write to disk and the amount of IO bandwidth used :

iotop -o -b -d 10
iotop -o -b -d 10 -u kevin

inxi

Usage

Flags

ipcs

Usage

Flags

Example

example 1

install

Usage

Flags

inotifywait

Installed with the Debian package

Usage

Flags

Example

Experimenting with inotifywait :

Alternate solution

Alternate solution to detect the creation of a file :

ionice

Usage

Flags

Example

Set the ionice value of the process having the PID 9799

Display the ionice value of the process having the PID 9799

Set the actual shell to idle priority :

iftop

Usage

Flags

Example

Monitor usage of interface eth0 :

innotop

Flags

interactive-mode keys :

Example

Start an innotop session :

iostat

Usage

Flags

Example

NFS report updated every 2 seconds :

id

Usage

Special uid's

Flags

ip

Usage

Synopsis :

Example

ip link :

Get interface status (name + up/down status + MTU + MAC address) :

Turn interface up/down :

ip addr :

Get interface status :

Assign IP address to interface :

Create a virtual interface :

ip route :

ip rule (source) :

iotop

Installed with the Debian package

Usage

Flags

Example

How to find which process is regularly writing to disk? (source)