Cutting or tearing an item may involve any of the following Biblical and Rabbinical prohibitions: Cutting, Fixing, Tearing, erasing letters, destroying a vessel, grinding, and doing a mundane act. Below the details of when each prohibition applies will be explained. One is only allowed to tear or cut something on Shabbos if none of these prohibitions are applicable. It is thus incumbent for the reader to read through the entire section prior to deducing permissible forms of tearing and cutting. When explained in the summaries and Q&A below that something is allowed, all the possible prohibitions were taken into account, and thus may be relied upon in actuality.
Prohibition #1: The/Koreah/Tearing prohibition
The laws of Tearing sewn items and separating glued items on Shabbos
1. The rules of the prohibition and when it applies:
A. The Principal prohibition-Tearing with intent to re-sew:
One who tears [an item] with intent to re-sew it, in the way to be explained below in B, is liable [to bring a sin offering] being that [doing so] is amongst the principal Shabbos prohibitions. As in the Tabernacle a skin curtain which a worm had fallen on and drilled into it a small round hole, [then] in order to sew it one would need to tear the hole from above and below in order so the sewing not be made in overlaps. Thus one who tears without intent to sew is exempt [from Biblical liability of the sewing prohibition] although doing so is Rabinically forbidden [as will be explained].
B. Tearing without intent to re-sew:
Although one who tears is not liable unless done on condition to re-sew it [afterwards] nevertheless it is Rabbinically forbidden in all scenarios [even when destroyed without intent to re-sew].
C. Tearing with intent to sew but not in a better way than done originally:
One who destroys a building with intent to return and build it, or one who tears with intent to return and sew, is not Biblically liable unless his intent is that the latter building be greater than the former, and by sewing that the [torn] cloth [be re-sewn to a better result than it was originally prior to the tearing]. As without the destroying and tearing it is completely impossible to fix the building and cloth that they be improved.
Other Opinions-Even by destroying no need for improvement: There are opinions which say that even by actions of destruction it is not necessary that the improvement be better than the way it was originally.
Other Opinions-One is liable for work even if not done for use of its body: All the above is in accordance to those which say that an action which is not done for the need of its body one is exempt on and is only Rabbinically forbidden. However there are opinions which argue on this and say that even work which is not done for the need of its body one is Biblically liable for.
The Final Ruling: [Due to the above lenient opinion one] therefore does not need to reprimand people who are lenient [to ask a gentile in a time of distress to destroy an item when they do not plan to rebuild it in a better] being that they have upon whom to rely. However every person should be stringent upon himself like the first opinion which is the main [Halachic] opinion.
D. Prohibition only applies by tearing apart many entities:
(Regarding [the] tearing [prohibition] there is only a prohibition [involved] when one tears and separates many entities which have [become] attached, such as one who tears a garment woven from many threads. However paper which is a single entity does not contain within tearing it or cutting it the tearing prohibition.) For other opinions see footnote
E. The law if the sewing was only meant to last temporarily:
If a launderer sewed the collar [of a shirt together], or [in a case that] a pair of shoes have been sewed together in the way that is done by professionals, then it is forbidden to cut them or to tear them from each other
The reason for this is: because by sewing there is no difference whether it was made to last or not to last, and destroying the sewing always contains [the] tearing [prohibition]. Now, although one who tears is not liable unless done on condition to re-sew it [afterwards] nevertheless it is Rabbinically forbidden in all scenarios [even when destroyed without intent to re-sew].
Other Opinions: [However] there are opinions which allow tearing or cutting stitches that was not made to last.
The Final Ruling: The main Halachic opinion is like the latter opinion, although nevertheless one should not be lenient in front of an ignoramus.
Summary: Cutting and tearing sewn threads:
The tearing prohibition applies when one tears or separates two entities from each other, even if one does intend to reattach them, if the attachment was meant to last. The tearing prohibition does not apply by tearing a single entity. If the sewn items were meant to be eventually torn then it may be torn, however not in the presence of an ignoramus.
In all cases that there is no tearing prohibition involved in tearing an item one must verify that there is as well no cutting and fixing prohibition involved in doing so.
2. Tearing leather:
It is permitted [for a person] to tear leather that covers the mouth of a barrel of wine [or other liquids] as explained in chapter 314 [Halacha 12], [when done for a Shabbos need. One need not worry (about any tearing prohibition involved in doing so)]
The reason and avoiding the cutting prohibition-340/17: Being that the leather is a single entity, [thus] the tearing prohibition is not applicable to it, but rather only the prohibition to cut it if he is particular to cut it to a specific measurement as explained there [in chapter 314/16].)
The reason- 314/12:A person may tear the hide which [seals] the opening of the barrel of wine when done for ones needs of Shabbos because tearing a detached item is allowed to be done even initially.
Avoiding the fixing prohibition: [However this is only allowed] as long as one does not intend to make something similar to a drainpipe out of the torn skin [I.e. a funnel] being that doing so is considered like fixing a vessel.
A piece of leather may be torn if one does not tear it into any specific measurement and does not make it into a new use through tearing it. It is thus permitted to tear the leather cover of a barrel in order to pour from the bottle.
3. Separating papers and other items that are glued together:
One who separates attached papers is [liable for doing] an offshoot of [the] tearing [prohibition], as one who attaches papers or skins with glue of the scribes and the like is [doing] an offshoot of the sewing [prohibition] and he is liable [and the tearing prohibition applies to all cases that the sewing prohibition applies].
Separating items which were accidently attached: However this only applies when the attachment was done for it to last, however pages of books which have been attached to each other through wax [which fell on them] or at the time of their binding, are permitted to be opened on Shabbos.
The reason for this is: as since [this attachment] was not made to last and furthermore it was done on its own without intent, therefore it is not at all similar to sewing, and it does not contain [the] tearing [prohibition].
Summary-Separating glued items:
It is forbidden to separate glued items if the items were glued to be permanently attached. If they are not meant to be attached and were accidently glued on their own, as occurs during book binding that glue or wax attaches pages together, then they may be separated on Shabbos.
May one separate items that were intentionally glued for temporary use?
This may be done, however not in the presence of an ignoramus as rules Admur regarding tearing a temporary stitch.
May one cut attached pages of a new book which were forgotten to be cut during the binding?
No, [as doing so involves the prohibition of fixing a vessel].
May one tear glued pages of a book if doing so will tear some of the letters or the paper?
Will tear letters: It is forbidden to be done due to the erasing prohibition.
Will tear part of the paper: Some have written against doing so [even according to Admur which holds there is no tearing prohibition in tearing a single entity] due to that it is fixing a vessel.
Summary: Cutting and tearing sewn threads:
Threads which were sewn for temporary usage and are meant to be eventually torn may be torn on Shabbos so long as one does not do so in the presence of an ignoramus.
4. Removing entangled clothing from thorns:
One whose clothing became tangled in thorns is to remove it in private [see footnote] and [carefully by] taking his time [to remove it], in order so it not tear. And if it [nevertheless] tears [despite ones being careful] then this is [Halachicly] meaningless being that one had no intent to do so and it was not an inevitable occurrence, as since he [was careful to] slowly remove it, it was possible for it not to tear.
5. Breaking an almond using a cloth:
It is permitted to break an almond with a cloth and we do not suspect that perhaps it will tear, as will be explained in chapter 508 [Halacha 3].
Prohibition # 2: Tikkun Keli-Fixing an item for a usage in the process of cutting it
1. Cutting an item to make a use for it: 
Cutting an item with a knife to make a use with it: Although cutting items detached [from the ground] is initially permitted when one is not particular to cut it in a specific measurement, as explained in chapter 314 [Halacha 16] nevertheless if through doing so one fixes the item to be used for a certain use, then he is liable for [the] “fixing a vessel” [prohibition] if he cut it using a knife as was explained in chapter 322 [Michaber Halacha 4] regarding the cutting of a twig.
Tearing it with ones hands to make a use of it: If it was done without a knife then one is exempt [from Biblical liability], although it is [Rabbinically] forbidden.
Summary of cutting an item to make it fit for a use:
Is forbidden to be done whether using a knife [in which case it is Biblically forbidden] or ones hands [in which case it is Rabbinically forbidden].
2. Breaking earthenware and tearing paper for a use:
Due to the above one may not break earthenware and may not tear paper which is permitted to move [i.e. is not Muktzah] in order to use the [torn or broken piece] for a use due to that doing so is similar to him fixing a vessel. See Chapter 508 [Halacha 2]
It is forbidden to break off a piece of earthenware or a piece of paper in order to make it fit for a use.
Making a hole in a vessel:
Is Biblically forbidden when made for both entering and removing items through the hole, or when intentionally made into elegant hole, due to the prohibition of fixing a vessel. It never carries with it the building prohibition.
Is Rabbinically forbidden when made for only entering items through the hole, or for only removing items through it.
Is totally permitted when it is not intended to be made for either entering or removing items through it, and is rather consequently made due to an action that one does.
May one widen an already existing hole? It carries the same laws as one who initially makes the hole on Shabbos.
3. Examples of cases which involve fixing a vessel:
A. Tearing an item in the process of barbecuing fish on Yom Tov:
Tearing a piece of paper to place under the fish: One who roasts fish over a grill is not to cut a piece of paper in order to soak it in water and then place it under the fish over the grill in order to prevent the fish from burning.
Breaking a piece of earthenware to place under the fish: Similarly one may not break a piece of earthenware in order to place it under the fish.
Breaking open cane to place its sheath under the fish: Similarly one may not break open a cane in order to place its sheath under the fish.
Making the cane into a skewer: As well, one may not break open the cane to make it into a figure like skewer to roast with.
The reason for all the above restrictions is: because in all cases that one makes and fixes an item to be fit for a use, then it is like he has fixed a vessel on Yom Tov.
B. Cutting a vine to fit a use:
Using a vine as a rope to help draw water with: A [detached] vine which has its head split like a fork and is [thus] fit to [use to] hang a bucket on and [use to] draw [water] with [such as to place it down a well to draw water, using the vine as a rope to place it down and bring it back up], then even if one thought about this from before Shabbos to use the [vine] to [help] draw [water] with on Shabbos, [nevertheless] it is forbidden to use it to draw with, unless the vine was tied to the bucket from before Shabbos.
The reason for this is: due to a decree that perhaps the vine will be too long for him, and one will cut it, being that it is soft and easy to be cut, and will thus end up [transgressing the prohibition of] fixing a vessel on Shabbos.
C. May one remove a reed from ones broom?
It is forbidden to remove a reed from a broom which is used to clean the house, being that through removing it he is fixing it for the use that he wishes to use it for, which is for hitting the children with, and [the law is that] any item that one fixes to be used for any use is included in the prohibition of fixing vessels. [Furthermore] even through a gentile it is forbidden to remove it, meaning [to even have him] detach it and remove it out from under the binding area of the broom, and it goes without saying that it is forbidden to [ask a gentile to] break the reed off from the broom, as by breaking it there is an additional prohibition [being transgressed which is] breaking a vessel, as will be explained in chapter 337 [Halacha 3]. However when one removes out an entire reed [from the broom] there is no [additional prohibition involved] of destroying a vessel, as this is similar to a vessel assembled by placing many pieces together, which does not contain [the prohibition of] destroying [a vessel] when taking it apart, unless the [attached pieces] were inserted [in their sockets] strongly and professionally.
D. Using a twig as a tooth pick:
A twig which is not animal food, even to take it in order to pick his teeth is forbidden [due to it being Muktzah, and to cut a piece off is forbidden also due to the fixing a vessel prohibition].
E. Cutting a knot:
Cutting the sewing and knot of a tailor: If the collar of a shirt had already been opened [after being made] but a professional [tailor] returned and sewed [the two sides of the collar] together in the way done by professionals, or if the professional tied it [in a way] that one is unable to untie it, then it is forbidden to cut the strings.
However this [prohibition to cut an undoable knot] only refers to a knot tied by the professional prior to having finished making the clothing, being that then the cutting of the strings of this knot involves the [prohibition of doing a] “Finishing touch”, as this finalizes the work needed to be done to the clothing being that through doing so the clothing is now fit to be worn, while until this was done it was never yet fit to be worn, [and it is thus forbidden as] any [action] done which is the finishing stroke [of the making of the vessel] contains [the prohibition of] “Finishing Touch” as was explained in chapter 302 [Halacha 5]
Cutting the knot of the launderer: However other knots which were tied after the clothing had finished having its work done to it, such as the knots of the laundering or the strings of a cloak which have been tied and one is not able to undo, [then] it is permitted to cut them.
Nevertheless, even so one may not be lenient [to cut it] in front of an ignoramus, and rather should do it privately.
By a knot made to last 7 days: If one is accustomed to only cut the strings [of the collar knot] upon changing the cloak from Shabbos to Shabbos , then it is forbidden to cut [the strings of the knot] just like it is forbidden to undo it [as will be explained in “The Laws of Tying and Untying on Shabbos”].
Summary: Cutting the strings of a knot:
Anytime it is permitted to open a knot on Shabbos one is likewise permitted to cut it. However one may not be lenient to cut it in front of an ignoramus, and rather should do it privately. [As well in a case that the knot attaches an item to the ground then the rope may not be torn even if one is allowed to untie the knot being that doing so involves the destroying prohibition.] Anytime that the knot is forbidden to be undone, it is likewise forbidden to be cut.
4. Tikkun Keli by foods:
Using straw or hay as a tooth pick: Therefore it is permitted to cut even with a knife [even into a particular measurement] straw or hay and [use it] to pick at his teeth [i.e. to use as a toothpick].
Using a twig as a tooth pick: However a twig which is not animal food, even to take it in order to pick at his teeth is forbidden [due to it being Muktzah, and to cut a piece off is forbidden also due to the fixing a vessel prohibition].
Plucking a leaf from a branch to use as a funnel: Plucking a leaf from a detached branch in order to place it into the hole of the barrel, is prohibited due to [the prohibition of] “fixing a vessel”, as any item which is alterated on Shabbos so it be fit to be used for a given purpose carries with it [the prohibition of] “fixing a vessel”.
The reason for why this is forbidden even if the leaf can be used for animal fodder:  Even if the leaf is soft and is [thus] fit to be eaten by animals, nevertheless it is prohibited to pluck it due to “fixing a vessel”. As [the Sages] only said that [modifying] animal fodder [into a vessel] does not carry with it the prohibition of “fixing a vessel” being that they are soft and do not last, as will be explained in chapter 322 [Halacha 4], in a case that one modifies the food to become an independent vessel, such as cutting a piece of straw to use as a toothpick in which case it is not considered like one is fixing a vessel being that it is not at all common to initially make a vessel out of food, due to the fact that it does not last long. However it is common to [use food] to modify through it a vessel that is already made, such as to place the leaf in the hole of the barrel which is already made. Therefore when one plucks [the leaf out from the detached branch] for this purpose this removal carries with it [the prohibition of] “fixing a vessel”.
Summary of Tikkun Keli by foods:
All foods that are edible for animals do not contain the Tikkun Keli prohibition and may thus be cut for the purpose of making a use out of the torn piece. It however may not be cut for the purpose of attaching the food to a vessel.
May one fix a vessel through using food parts, such as to carve a piece of vegetable to be fit to be used as a funnel for a barrel?
No, doing so may be Biblically forbidden.
Prohibition # 3: Michateich-The prohibition of cutting an item to a required size
1. The principal prohibition:
One who cuts hide and is particular to cut it to the exact size that he needs, such as for example he is cutting it for straps and for sandals, this is a principal form of forbidden work, being that in the [process of building the] Tabernacle they would cut the skin of rams or techashim to an exact size to be made a cover for the tent.
2. The offshoot prohibition: 
Anyone who cuts any given item which is detached [from the ground] and is particular to cut it to a specific size, is [doing an action which is] an offshoot of [the primary] cutting [prohibition].
3. Examples: 
Cutting a feather to a specific size: For example, one who cuts off the head of a feather, which is thin and soft and is [thus] fit to be used [to cushion] a pillow or a blanket with, then he is liable if he intends to [use it for this] being that one is particular to cut it to the exact size that is fit for him.
Sanding down a pole: Similarly one who sands down the head of a wooden pole so that it is smooth and sharp, is liable for [the] cutting [prohibition].
It is forbidden to cut an item to a specific measurement due to the Mechateich prohibition.
Prohibition # 4: The prohibition of cutting an item to small pieces
1. The prohibition to cut an item into small pieces:
By wood: [Furthermore] even if one is not meticulous on the sizes, if he cuts [wood] into very thin pieces in order to light fire [with them], then he is liable for [the] grinding [prohibition].
By Other items: [As well] other detached items ….are only allowed [to be cut] …. if one does not cut them into very small pieces [and only if none of the other explained prohibitions apply].
It is forbidden to cut wood or other items to small pieces due to the Grinding prohibition.
Prohibition # 5: The prohibition of doing a Mundane act
1. The prohibition of doing a mundane act even if no actual prohibited work is involved:
However one who cuts [the wood] into big pieces and is not meticulous about their size, then it only contains a Rabbinical prohibition [which was prohibited] because it is a mundane action and [thus] disgraces the Shabbos. [This is prohibited even] when doing so does not contain the [prohibition of] moving Muktzah, such as by wood which was designated for a use and is [thus] prepared to be moved.
Prohibition #6: The Destroying prohibition
See “The laws of Building and destroying on Shabbos” for the full details of this prohibition. The following is its summary:
One may only destroy a vessel [as opposed to disassemble] if:
- It is not attached to the ground And
- It cannot hold 40 SeahAnd
- It is considered a non-sturdy vessel [or is sturdy but one asks a gentile to break it as will be explained]And
- One does not intend to make a nice looking openingAnd
- One needs to destroy it for a Shabbos need.
Cases of tearing which do not contain any prohibition:
1. The conditions needed to be allowed to cut an item on Shabbos:
[Although cutting wood even to big pieces is forbidden due to it being a mundane act, nevertheless] other detached items which cutting is 1) not considered a mundane action are allowed [to be cut] as long as 2) one does not have intent to cut them to a specific size and 3) does not cut them into very small pieces, as well as 4) that it is an item that does not contain [the prohibition of] fixing a vessel in cutting it as will be explained in chapter 340 [Halacha 17], [as well as 5) It does not contain the tearing prohibition, as well as 6) It does not contain a destroying prohibition, as well as 7) it does not contain an erasing prohibition].
2. Cutting the strings wrapped or sewed around food: 
The string wrapping around a chunk of meat: Based on this it is permitted to cut the knots of a spit which are tied around a lamb or chicken that are roasting on it.
Sewing of stuffed chicken: Similarly stuffed chickens which are sewed shut one is allowed to cut the string of the sewing.
3. Breaking the rope that secures a cover to its vessel:
Seals that are on vessels, such as a chest of drawers, box and portable tower which have their covering tied to them with a rope, it is permitted to cut the rope even with a knife or undo [the rope even] through taking apart its threads, in order to open [the box] to remove its content.
Undoing its knot: It goes without saying that it is allowed to undo the knot as it is not a permanent knot being that it is meant to be constantly removed.
The reason that this does not contain a destroying prohibition: Now, although the rope is made to attach the cover to the vessel, and thus when one cuts it or undoes it he is destroying this attachment, [nevertheless] this does not contain the [prohibition of] destroying as the rope [only gives the cover] a weak attachment [to the vessel] being that it is not that strong, and thus when one destroys it one is destroying an incomplete [non-sturdy] vessel [which is allowed as the] destroying [prohibition] only applies by vessels when destroying a complete [sturdy] vessel.
4. Breaking through woven palm leaf baskets in order to get the food inside:
Baskets that are used for figs and dates, which are vessels that are made from palm leaves and have placed in them figs or dates that have not [yet] ripened in the sun in order so they completely ripen [in the basket], then if the cover is tied to them with a rope, it is permitted to unravel the rope or cut it as explained [in the] above [Halacha].
[Furthermore] even the actual body of these vessels are permitted to be unraveled and cut, as the structure of these vessels which are made of palm leaves are a week structure which is not made to last long, and [thus] when breaking it, it is only considered as if one is breaking hazelnuts and almonds in order to get the food that is in them.
5. Breaking the ropes that tie a door to a pit:
Seals that are on the ground, such as the door of a pit which is tied to it with a rope is permitted to be untied being that the knot was not made to last long, as it is meant to be constantly untied. However if one is unable to undo the knot then it is forbidden to undo the threads of the rope or to cut it due to [the] destroying [prohibition], as every item attached to the ground has [a] building and destroying [prohibition] even if it is not a complete [sturdy] vessel.
The law by a door not made to last: However this only applies by a door that is made to last [on the pit] and not be removed on Shabbos, and thus when one wants to open the pit he unties the rope and opens the door [and then replaces it] and does not totally remove the door from there, as it is set to be there for some time. However if [the door] is not made to last at all then there is no destroying [prohibition] involved neither in unraveling the rope or cutting it, and not even in removing the actual door from it, unless it is a case that the door revolves on hinges and [to remove it] one must remove the hinge from its socket as will be explained.
May one cut an item on Shabbos?
It is only permitted to cut an item if all of the following conditions are fulfilled:
- It is a single entity, such as a piece of leather or [non-Muktzah] wood, as opposed to a cloth. Thus one may not separate two pieces of paper or plastic that has been intentionally glued or sewn together [even not to last].
- One is not cutting it to a specific measurement.
- Doing so is not making it useable now for a new use.
- One does not cut it to very small pieces.
- One does not break apart any words in doing so.
- The item is not considered a sturdy or complete vessel, or is but is not meant to last at all.
- Does not contain a mundane act which is a disgrace to Shabbos.
- One is doing so for a Shabbos need.
One may cut the following items in order to take out the food or objects that are within them:
- A piece of leather that is serving as the cap of a bottle.
- Strings that are tied around food, such as by a stuffed turkey, or that are tied around the cover of vessels in order to secure them onto the vessel.
- A basket made of weak material which is not made to last long and has food inside.
May one tear a piece of cotton from a cotton ball or cotton sheet?
Doing so is forbidden due to the prohibition of “fixing a vessel” [see footnote regarding the tearing prohibition], and if one is particular to cut it to specific measurements then it is also forbidden due to the cutting prohibition. 
May one tear toilet paper?
Doing so is forbidden due to the tearing prohibition [even according to Admur] [as well as the fixing a vessel prohibition], and if it is cut by the perforated lines then it also possibly contains the cutting prohibition.
If one has nothing else available, then he should use writing paper [even if Muktzah] to wipe with. If this too is not available then some Poskim allow one to cut [a larger than needed piece of] toilet paper not on the vertical lines using an irregularity.
Others say that one is to wipe with it and without tearing it, place it into the toilet and then flush.
May one separate plastic ware which is attached together, such as two plastic spoons which are attached or two yogurts which are attached?
No. This is forbidden due to the fixing a vessel prohibition. [Seemingly however according to those opinions that permit opening disposable cans likewise here it would be permitted to separate the above disposable items. See The Laws of Building and Destroying Chapter 2 Halacha 9 Q&A!]
May one separate a two part ices?
No. This is forbidden due to the fixing prohibition. [Seemingly however according to those opinions that permit opening disposable cans likewise here it would be permitted to separate the above disposable items. See The Laws of Building and Destroying Chapter 2 Halacha 9 Q&A!]
May one open up an envelope?
It is permitted according to all to tell a gentile that he cannot read the letter until it is opened and have the gentile understand that he wants him to open it.
May one cut a piece of tape?
Even according to those which permit in times of need the use of tape to attach a bandage to ones wound, this only applies if the piece of tape was cut from before Shabbos, as cutting it on Shabbos poses a “Cutting” prohibition. [However the tape may be cut on Shabbos to a larger size than needed, in a case of need, such as for a wound.]
May one cut or tear a bandage to make it a better fit?
Doing so is forbidden due to the “Make Bepatish” prohibition.
 Lit. and
 317/6: One is not liable for [the] tearing [prohibition] unless he [tears it] with intent to re-sew.
 302/4; 317/7
 This answers a question raised on the Michaber 340/ 13[brought in Peri Megadim and Biur Halacha Ein Shivrim] which writes that if one tears paper he is liable for Tikkun Keli, and thus the question is asked why one is not liable for also tearing. Thus Admur suggests that by a single entity it does not apply. However see next footnote
 The Mishneh Berurah in Biur Halacha “Eiyn Shovrin” argues on Admur and says that the prohibition applies even when tearing a single entity. He suggests to answer the question mentioned in the above footnote that the tearing prohibition only applies when there is benefit to both sides being torn, as opposed to by paper that one is tearing it to simply use the torn piece and thus the other side does not benefit. He concludes with a Tzaruch Iyun. To note that there are Poskim [Minchas Yitzchak 1/77] which have learned from this Biur Halacha then when tearing in a way of destruction it is completely permitted. The Tzitz Eliezer seems to side with Admur’s ruling, as is evident from his leniency by cotton balls, [see Q&A]
 In such a case it is Rabbinically forbidden. It is Biblically forbidden if torn with intent to re-sew, and according to some only if one has intent to re-sew in a better way than it was originally.
 Minchas Yitzchak 8/31
 Piskeiy Teshuvos 340/31
 SSH”K 28/1 footnote 4; Piskeiy Teshuvos 340/31
 SSH”K 28 footnote 5 in name of Rav SZ”A; Piskeiy Teshuvos 340/31. There they write that it contains a tearing prohibition [according to the M”B in contrast to Admur] and a “fixing a vessel” prohibition.
 So explains the Karban Haeidah on Yerushalmi 7/2. The reason for this is so it not appear to others like he is fixing a vessel.
However the Pnei Moshe explains that it means that the case is referring to that thorns got stuck onto his clothing and have penetrated inside [Tzina-private-here means inside] and he desires to remove them to prevent the thorns from causing him pain. Vetzaruch Iyun as to which commentary Admur agrees with.
 There it is explained that cutting wood to a desired measurement is Biblically forbidden.
 This will be brought below in Halacha 4
 There Admur brings different cases that tearing or breaking an item is forbidden due to one making it now fit for a use.
 314/2 and 3
 Lit. a branch
 Meaning out from the area where all the reeds have been fixed into.
 Michaber 322/4
 If done with one’s hand it is Rabbinically forbidden, and if done with a vessel is Biblically forbidden. [M”B 13]
 Michaber 322/4
 M”B 322/9
 M”B 322/10
 In which case it would normally contain the cutting prohibition, although here it is allowed being that it is a food, and by foods the cutting prohibition is not applicable. [M”B 322/12]
 If done with one’s hand it is Rabbinically forbidden, and if done with a vessel is Biblically forbidden. [M”B 322/13]
 Meaning we do not suspect that one will come to pluck a leaf from a tree, however from a branch that had been previously cut off, we do suspect.
 Of the Michaber. This chapter of the Alter Rebbe’s Shulchan Aruch did not make it to print.
 M”B 322/11
 Its laws were explained in Halacha 5 above. The only difference between this case and a vessel made up of individual parts is with regards to that the latter is allowed to be destroyed even not for a Shabbos need. [See Ketzos Hashulchan 119 note 18]
 The only difference between this case and a vessel made up of individual parts is with regards to that the latter is allowed to be destroyed even not for a Shabbos need. [See Ketzos Hashulchan 119 note 18]
 See also chapter 308 Halacha 54 and 55
 As opposed to untying the actual knot, which will explained below.
 However if they were sewn not to last, then they may be torn when not in the presence of an ignoramus.
 Otherwise this is a problem of tearing as explained in Chapter 340 Halacha 17
 Otherwise is a prohibition of “Cutting”. -Halacha 16
 Otherwise it is a prohibition of Fixing a vessel. -Halacha 16 here and chapter 340 Halacha 17
 Otherwise it is a prohibition of “Grinding”- Halacha 16
 Otherwise is a prohibition of “Erasing” Chapter 340 Halacha 4
 Otherwise it is a prohibition of “Destroying” Halacha 17
 Otherwise it is Rabbinically forbidden. Halacha 16
 Otherwise its problematic due to the destroying prohibition. See Ketzos Hashulchan 119 note 34.
 According to the M”B and others [in contrast to Admur] it is also forbidden due to the tearing prohibition. [Minchas Yitzchak 4/45; Tzur Yaakov 152]
 So rules that it is forbidden: Minchas Yitzchak 4/45; Tzur Yaakov 152
 Tzitz Eliezer 13/45; Rav Shlomo Zalman Aurbauch in SSH”K 35 footnote 48
 So writes Tzitz Eliezer ibid. As otherwise this would be forbidden to be done due to the fixing a vessel and cutting prohibition. Vetzaruch Iyun from Piskeiy Teshuvos and SSH”K in footnote ibid which do not mention how one is to avoid the Tikkun Keli prohibition, and it seems they learn it never applies to begin with. Vetzaruch Iyun Gadol.
 Piskeiy Teshuvos 340/28
 As the toilet paper is made up of many different pieces. [Nishmas Adam, Az Nidbaru 2/31, as opposed to Chelkas Yaakov 3/123 which stated that according to Admur there is no tearing prohibition involved with paper.]
 Chelkas Yaakov ibid; Sheivet Halevy 1/115
 SSH”K 23/16; Piskeiy Teshuvos 340/28
 Chelkas Yaakov ibid; SSH”K 23/16
 To avoid the fixing a vessel prohibition. [See Tzitz Eliezer ibid]
 Az Nidbaru 2/79
 Piskeiy Teshuvos 314/3
 Piskeiy Teshuvos 340/29
 Ketzos Hashulchan 119 note 34 as although the envelope is considered an un-sturdy structure, nevertheless since there is no Shabbos need involved in opening it, meaning that reading the letter is not a Shabbos necessity, therefore it is forbidden, as destroying a non-sturdy vessel was only allowed in order to remove what is inside for a Shabbos need, as explained in 314/1. So rules M”B 340/41 in name of different Poskim. The Peri Chadash holds that it contains a Biblical prohibition while the Chacham Tzevi maintains that it contains a Rabbinical prohibition.
 Chazon Ish, and so leans to rule Rav SZ”A in SSH”K 28 footnote 15, Shut Even Yisrael 16
 So rules M”B ibid
 Piskeiy Teshuvos 328/21
 Tzitz Eliezer 8/15-14-6
 Piskeiy Teshuvos 328/21