ispell [options] [files]

Compare the words of one or more named files with the system dictionary. Display unrecognized words at the top of the screen,
accompanied by possible correct spellings, and allow editing via a series of single-character commands that are case-insensitive.

isovfy isoimage

Verify the integrity of the specified ISO9660 image and write the results to standard output.

isosize [option] iso9660-img-file

Display the length of an ISO9660 filesystem contained in the specified file. The image file can be a normal file or a block device such
as /dev/sr0. With no options, the length is displayed in bytes. Only one of the two options can be specified.

Options
-d num
Display the size in bytes divided by num.
-x Display the number of blocks and the block size (although the output refers to blocks as sectors).

isoinfo [options]

Display information about ISO9660 images. You can use isoinfo to list the contents of an image, extract a file, or generate a find-like
file list. The -i option is required to specify the image to examine.

Options
-d Print information from the primary volume descriptor (PVD) of the ISO9660 image, including information about Rock
Ridge and Joliet extensions if they are present.
dev=target
Set the SCSI target for the drive.

isodump isoimage

Interactively display the contents of the ISO9660 image isoimage. Used to verify the integrity of the directory inside the image.
isodump displays the first portion of the root directory and waits for commands. The prompt shows the extent number (zone) and
offset within the extent, and the contents display at the top of the screen.

iptables-save [options]

System administration command. Print the IP firewall rules currently stored in the kernel to stdout. Output may be redirected
to a file that can later be used by iptables-restore to restore the firewall.

Options
-c, --counters
Save packet and byte counter values.
-t name, --table name
Print data from the specified table only.

iptables-restore [options]

System administration command. Restore firewall rules from information provided on standard input. iptables-restore takes
commands generated by iptables-save and uses them to restore the firewall rules for each chain. This is often used by initialization
scripts to restore firewall settings on boot.

Options
-c, --counters
Restore packet and byte counter values.
-n, --noflush
Don’t delete previous table contents.

iptables command [options]

System administration command. Configure netfilter filtering rules for kernels 2.4 and later. Rules for iptables consist of some
matching criteria and a target, a result to be applied if the packet matches the criteria. The rules are organized into chains. You can
use these rules to build a firewall, masquerade your local area network, or just reject certain kinds of network connections.

ipcs [options]

System administration command. Print report on interprocess communication (IPC) message queues, shared memory segments,
and semaphore arrays for which the current process has read access. Options can be used to specify the type of resources to
report on and the output format of the report.

ipcrm [options]

System administration command. Remove interprocess communication (IPC) message queues, shared memory segments, or semaphore
arrays. These may be specified either by numeric identifier or by key, using the following options.