When you type commands on a computer, you’re talking to the shell. It’s like a translator between you and the computer’s brain. Two main types of shells are the Bourne Shell (SH) and the Bourne Again Shell (Bash), each with its own way of understanding and doing things. Let’s explore the difference between SH and Bash and how they help us work with computers.
sh
#!/bin/sh
bash
#!/bin/bashWhat are SH and Bash?
SH, the original Bourne Shell, was introduced in the 1970s as the primary shell for Unix. Stephen Bourne at Bell Labs developed it, hence the name. SH is known for its simplicity and portability. It is a reliable option when creating scripts that might be executed on various Unix derivatives.
Bash, on the other hand, stands for Bourne Again SHell. It’s an improved version of the original SH, developed by Brian Fox for the GNU Project as a free software replacement for the Bourne Shell. Bash is the default shell for many Linux distributions and macOS. It includes features from other shells like KornShell (ksh) and C shell (csh), offering more robust functionality and scripting capabilities.
Key Differences Between SH and Bash
Syntax Differences:
Bash provides more shorthand and enhanced scripting syntax compared to SH. For example, in bash, you can use the double square bracket syntax [[ ]] for tests, which is more robust and safer than the single bracket syntax [ ] used in SH.
# SH Syntax
if [ $a -lt $b ]; then
echo "$a is less than $b"
fi
# Bash Syntax
if [[ $a -lt $b ]]; then
echo "$a is less than $b"
fiArray Variables:
Bash supports array variables, whereas SH does not. Arrays can be useful when you need to work with multiple values stored under a single variable name.
# Bash Syntax
array=("one" "two" "three")
echo ${array[1]} # Outputs "two"Command Line Editing:
Bash supports command line editing, whereas this is not standard in SH. In Bash, you can navigate the command history using arrow keys, delete text with backspace, and use tab completion to complete file names and command names.
Shell Options:
Bash comes with additional shell options compared to SH. For instance, the shopt command in Bash provides the ability to change additional shell optional behavior which is not available in SH.
Process Substitution:
Bash supports process substitution (<(command) and >(command)), allowing a process’s input or output to be referred to using a filename. This feature is not available in SH.
# Bash Syntax
diff <(command1) <(command2)Command not found Hook:
Bash has a special shell function command_not_found_handle that is executed when a command is not found. This feature is not available in SH.
Here Strings:
Bash supports “Here Strings” which is a form of I/O redirection allowing a string to be used as the input for a command, denoted by <<<. This feature is not available in SH.
# Bash Syntax
wc -l <<< "This is a string"
Note
- A shell is an interface between the end-users and the operating systems.
- sh implements the shell command line interpreter.
- bash is a superset of sh.
In line with our commitment to enhancing your skills, we’re thrilled to announce the launch of our new blog series, “Mastering Bash Scripting for Embedded Linux Development”. This series aims to equip you with the knowledge and skills needed to excel in Bash scripting, particularly in the context of embedded Linux development.
Stay tuned as we delve deeper into the intricacies of Bash scripting, providing you with valuable insights and practical tips along the way. Happy scripting!
You can find the series:
1) Mastering Bash Scripting for Embedded Linux Development
Several circumstances can result in muscle loss, together with AIDS, continual obstructive pulmonary illness
(COPD), cancer, and kidney and liver disease.
Whereas not as widespread, AAS can be used in these populations
to help protect muscle mass (9, 10). To improve muscle power and power beyond the natural limit, some folks flip to substances like anabolic-androgenic
steroids (AAS). Yes, if you take prescription anabolic steroids under the supervision of your healthcare provider for a medical
purpose, anabolic steroids are usually safe.
This could be defined by incomplete restoration of the HPGA because of recent AAS use or prolonged or persistent hypogonadism from previous use.
A case-control examine also suggests that AAS use
leads to a persistent small reduction in testosterone
ranges (177). Nonetheless, current or current unreported AAS use, reverse causality and different components inherent to a case-control examine
design make it tough to ascertain a real cause-and-effect relationship.
Regardless, persistent AAS-induced hypogonadism has been reported in the
literature in a quantity of circumstances (65, 178). Future research is needed to delineate the AAS cycle features or affected person traits that hinder restoration and result in partially reversed, prolonged,
or persistent hypogonadism. Serum creatinine levels are commonly used to estimate the glomerular
filtration rate (eGFR) utilizing formulation such
because the Continual Kidney Disease Epidemiology Collaboration (CKD-EPI)
equation (157).
However, since quite a few anabolic steroid consumers additionally took different
substances, it is difficult to prove that anabolic steroids were the
cause of these fatalities. The following are examples of how anabolic steroid usage impacts
the physique. Many customers report experiencing nervousness, mood swings, and aggressive habits.
It Is essential to acknowledge that while steroids can amplify bodily capabilities, they will also
cloud mental clarity. As A End Result Of of this, I really feel it’s
fairly rare that systemic steroids are needed, and in a
lot of the cases where they are (outside of life-threatening circumstances), low and short doses with fewer
unwanted side effects should be used. Additionally, in sufferers with schizophrenia, steroids
can often worsen an existing psychosis. Unfortunately, many doctors (particularly
ER ones who hardly ever have entry to a dermatologist they will
consult) will prescribe steroids despite not being sure of
the diagnosis.
For example, antidepressants for despair or analgesics for headaches and ache.
Whereas the drug may be beneficial to folks with autoimmune or immune-mediated ailments by blunting the exaggerated immune response,
doing so can leave an individual susceptible to other infections.
Because the potential for unwanted side effects is high and will increase the longer you utilize the drug, prednisone should
solely be used on a short-term foundation. Restoration from adrenal insufficiency
varies considerably among individuals. Whereas some
might regain their ability to produce cortisol independently inside a couple of days, others may take
weeks and even over a 12 months to completely restore the operate of the HPA axis.
This variability underscores the significance of personalized
medical steerage when discontinuing prednisone.
The regular use of steroids can even affect your pores and skin, which is why bodybuilders become susceptible to acne, as a sudden improve in testosterone
ranges can hyperactivate their sebaceous glands. Nevertheless, you
might not have the flexibility to spot them when the bodybuilders take the stage since they usually have
a heavy spray tan on. Some research in adults
suggest a hyperlink between long-term inhaled steroid use and
an elevated risk of breaking bones.
As such, they will start with 15 mg per day of the compound for the primary three weeks and improve it to twenty mg per day for the subsequent three weeks.
Anavar can be used by males as an effective substitute for
testosterone during their first cycle. But keep in thoughts that in this
case, it’ll help extra with fat loss quite than helping placed on sturdy muscle mass.
In hindsight, Anavar for males can serve as an essential
element of the chopping phase for increased fats burning and average lean muscle formation. Your doctor might say you’ll find a
way to cease the osteoporosis medicine when you have been only prescribed it because you have been taking steroid tablets.
But if your danger of breaking a bone is still larger, your physician may counsel staying on an osteoporosis
medication for longer, earlier than possibly having a pause in treatment after 5 years.
Testosterone can be prescribed for a quantity of hormone-related conditions,
corresponding to hypogonadism. Anadrol is an instance of a
steroid with both medicinal and performance makes use of.
Whether testicular shrinkage is everlasting or not depends on the potency of the dosage, and the period
for which steroids have been taken. Another issue arises with the fast development
of muscles and that’s stretch marks. Anticholinergics are also categorized as class C since in experimental
animals they have been shown to be teratogenic and
to trigger adverse effects [37, 47]. In the next
sections we’ll current extra detailed information on four
particularly at-risk clinical groups (children,
pregnant and nursing girls and aged subjects),
in addition to some uncommon clinical issues.
The NIDA stories four studies in which volunteers were given high dosages of anabolic
steroids. In three of the research, the volunteers reported greater feelings of aggression and irritability, although the consequences diversified widely between individuals.
This means your healthcare provider has given it to you as part of a therapy
plan. Prednisone is a half of a group of medication referred to as corticosteroids
(often known as “steroids”). Other steroid drugs embrace prednisolone, hydrocortisone, and methylprednisolone.
Tissue-specific models reported embody T cell-specific
or myeloid cell knockout of GR in addition to transgenic mice with thymus over- and under-expression of
GR. Some of the immune and inflammatory phenotypes of these
varied mice have been reviewed intimately elsewhere (Herold et al.,
2006; Kleiman and Tuckermann, 2007) and are discussed under.
It should also be famous that some anti-inflammatory effects of glucocorticoids are apparent
inside minutes and a quantity are impartial of the transcriptional results
of GR (see for instance Croxtall et al. (2002), Limbourg et al.
(2002) and Stellato (2004)). Many of those genes are generally
over-expressed throughout persistent non-resolving inflammation.
Corticosteroids or glucocorticoids—commonly referred to as steroids—are
prescription medicines that reduce inflammation within the body.
Irritation may be brought on by varied components, together with allergic reactions and autoimmune diseases similar to lupus and a number of sclerosis
(MS). Our bodies produce their own glucocorticoids in addition to one thing referred to as adrenocorticotropic hormone, or ACTH,
which is produced by the pituitary gland. ACTH stimulates steroid manufacturing and is typically prescribed as an alternative of glucocorticoids.
Doctors use these medicine to help deal with delayed puberty, and improve muscle
mass and power in people who have situations that
cut back muscle tissue. Some doctors prescribe it for testosterone supplementation therapy to enhance mood and sexual
efficiency in older men.
References:
legal Anabolics
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