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Fixes for spelling, grammar and formatting

Fixes for [spelling, grammar, formatting](https://github.com/Idnan/bash-guide/pull/5)
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Adnan Ahmed 2017-04-03 07:58:07 +04:00 committed by GitHub
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README.md
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@ -22,7 +22,7 @@
# 1. Basic Operations
### a. `export`
Displays all environment variables and if you want to get detail of specific variable then use `echo $VARIABLE_NAME`
Displays all environment variables. If you want to get details of a specific variable, use `echo $VARIABLE_NAME`.
```bash
export
```
@ -40,7 +40,7 @@ $ echo $SHELL
```
### b. `whereis`
Whereis search for executables, source files, and manual pages using a database built by system automatically.
whereis searches for executables, source files, and manual pages using a database built by system automatically.
```bash
whereis name
```
@ -51,7 +51,7 @@ $ whereis php
```
### c. `which`
which search for executables in the directories specified by the environment variable PATH. This command will prints full path of the executable(s).
which searches for executables in the directories specified by the environment variable PATH. This command will print the full path of the executable(s).
```bash
which program_name
```
@ -62,7 +62,7 @@ $ which php
```
### d. clear
Clears content on window
Clears content on window.
## 1.1. File Operations
<table>
@ -90,7 +90,7 @@ Clears content on window
</table>
### a. `ls`
Lists your files. It has a lot of options like `-l` lists files in 'long format', which contains the exact size of the file, who owns the file and who has the right to look at it, and when it was last modified. `-a` lists all files, including hidden files. For more information on this command check this [link](https://ss64.com/bash/ls.html)
Lists your files. `ls` has many options: `-l` lists files in 'long format', which contains the exact size of the file, who owns the file, who has the right to look at it, and when it was last modified. `-a` lists all files, including hidden files. For more information on this command check this [link](https://ss64.com/bash/ls.html).
```bash
ls option
```
@ -108,7 +108,7 @@ drwxr-xr-x 17 adnan staff 578 Mar 27 23:36 .git
</pre>
### b. `touch`
Creates or updates your file
Creates or updates your file.
```bash
touch filename
```
@ -118,7 +118,7 @@ $ touch trick.md
```
### c. `cat`
It can be used for the following purposes under UNIX or Linux
It can be used for the following purposes under UNIX or Linux.
* Display text files on screen
* Copy text files
* Combine text files
@ -130,7 +130,7 @@ cat file1 file2 > newcombinedfile
```
### d. `more`
Shows the first part of a file (move with space and type q to quit)
Shows the first part of a file (move with space and type q to quit).
```bash
more filename
```
@ -142,72 +142,72 @@ head filename
```
### f. `tail`
Outputs the last 10 lines of file. Use `-f` to output appended data as the file grows
Outputs the last 10 lines of file. Use `-f` to output appended data as the file grows.
```bash
tail filename
```
### g. `mv`
Moves a file from one location to other
Moves a file from one location to other.
```bash
mv filename1 filename2
```
Where `filename1` is the source path to the file and `filename2` is the destination path to the file.
### h. `cp`
Copies a file from one location to other
Copies a file from one location to other.
```bash
cp filename1 filename2
```
Where `filename1` is the source path to the file and `filename2` is the destination path to the file.
### i. `rm`
Removes a file. But if you will apply this command on a directory directory, it will gives you an error
Removes a file. Using this command on a directory gives you an error.
`rm: directory: is a directory`
So in order to remove directory you have to pass `-rf` to remove all the content of the directory recursively
In order to remove a directory you have to pass `-rf` to remove all the content of the directory recursively.
```bash
rm filename
```
### j. `diff`
Compares files, and shows where they differ
Compares files, and lists their differences.
```bash
diff filename1 filename2
```
### k. `chmod`
Lets you change the read, write, and execute permissions on your files
Lets you change the read, write, and execute permissions on your files.
```bash
chmod -options filename
```
### l. `gzip`
Compresses files
Compresses files.
```bash
gzip filename
```
### m. `gunzip`
Un-compresses files compressed by gzip
Un-compresses files compressed by gzip.
```bash
gunzip filename
```
### n. `gzcat`
Lets you look at gzipped file without actually having to gunzip it
Lets you look at gzipped file without actually having to gunzip it.
```bash
gzcat filename
```
### o. `lpr`
Print the file
Print the file.
```bash
lpr filename
```
### p. `lpq`
Check out the printer queue
Check out the printer queue.
```bash
lpq
```
@ -220,7 +220,7 @@ active adnanad 59 demo 399360 bytes
```
### q. `lprm`
Remove something from the printer queue
Remove something from the printer queue.
```bash
lprm jobnumber
```
@ -248,13 +248,13 @@ lprm jobnumber
</table>
### a. `awk`
Awk is most usefull command for handling text files. It operates on entire file line by line. By default it uses whitespace to separate the fields. The most common syntax for awk command is
awk is the most useful command for handling text files. It operates on an entire file line by line. By default it uses whitespace to separate the fields. The most common syntax for awk command is
```bash
awk '/search_pattern/ { action_to_take_if_pattern_matches; }' file_to_parse
```
Lets take following file `/etc/passwd`. Here's the sample data that this file contains.
Lets take following file `/etc/passwd`. Here's the sample data that this file contains:
```
root:x:0:0:root:/root:/usr/bin/zsh
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
@ -262,7 +262,7 @@ bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
```
So now lets get only username from this file. Where `-F` specfies that on which base we are going to separate the fields. In our case it's `:`. `{ print $1 }` means print out the first matching field.
So now lets get only username from this file. Where `-F` specifies that on which base we are going to separate the fields. In our case it's `:`. `{ print $1 }` means print out the first matching field.
```bash
awk -F':' '{ print $1 }' /etc/passwd
```
@ -288,14 +288,14 @@ _kadmin_admin:*:218:-2:Kerberos Admin Service:/var/empty:/usr/bin/false
_kadmin_changepw:*:219:-2:Kerberos Change Password Service:/var/empty:/usr/bin/false
_krb_kadmin:*:231:-2:Open Directory Kerberos Admin Service:/var/empty:/usr/bin/false
```
You can also force grep to ignore word case by using `-i` option. Also `-r` can be used to search all files under the specified directory like
You can also force grep to ignore word case by using `-i` option. `-r` can be used to search all files under the specified directory, for example:
```bash
$ grep -r admin /etc/
```
And `-w` to search for words only. For more detail on `grep`, check following [link](https://www.cyberciti.biz/faq/grep-in-bash).
### c. `wc`
Tells you how many lines, words and characters there are in a file
Tells you how many lines, words and characters there are in a file.
```bash
wc filename
```
@ -307,7 +307,7 @@ $ wc demo.txt
Where `7459` is lines, `15915` is words and `398400` is characters.
### d. `sed`
stream editor for filtering and transforming text
Stream editor for filtering and transforming text
*example.txt*
```bash
@ -331,7 +331,7 @@ Hello This is a Test d d d d
```
### e. `sort`
sort lines of text files
Sort lines of text files
*example.txt*
```bash
@ -374,7 +374,7 @@ e
```
### f. `uniq`
report or omit repeated lines
Report or omit repeated lines
*example.txt*
```bash
@ -411,7 +411,7 @@ sort example.txt | uniq -c
```
### g. `cut`
remove sections from each line of files
Remove sections from each line of files
*example.txt*
```bash
@ -427,7 +427,7 @@ riding park play
```
### h. `echo`
display a line of text
Display a line of text
*display "Hello World"*
```bash
@ -447,7 +447,7 @@ World
```
### i. `fmt`
simple optimal text formatter
Simple optimal text formatter
*example: example.txt (1 line)*
```bash
@ -481,7 +481,7 @@ amet.
```
### j. `tr`
translate or delete characters
Translate or delete characters
*example.txt*
```bash
@ -509,7 +509,7 @@ Baz!
```
### k. `nl`
number lines of files
Number lines of files
*example.txt*
```bash
@ -561,7 +561,7 @@ nl -s". " example.txt
```
### l. `egrep`
print lines matching a pattern - Extended Expression (alias for: 'grep -E')
Print lines matching a pattern - Extended Expression (alias for: 'grep -E')
*example.txt*
```bash
@ -602,7 +602,7 @@ ipsum dolor sit
```
### m. `fgrep`
print lines matching a pattern - FIXED pattern matching (alias for: 'grep -F')
Print lines matching a pattern - FIXED pattern matching (alias for: 'grep -F')
*example.txt*
```bash
@ -649,23 +649,23 @@ foo (Lorem|dolor)
</table>
### a. `mkdir`
Makes a new directory
Makes a new directory.
```bash
mkdir dirname
```
### b. `cd`
Moves you from one directory to other. If you just run
Moves you from one directory to other. Running this
```bash
$ cd
```
Then it will moves you to home. Also this command accepts an optional `dirname`, which if provided will moves you to that directory.
moves you to home directory. This command accepts an optional `dirname`, which moves you to that directory.
```bash
cd dirname
```
### c. `pwd`
Tells you in which directory you currently are
Tells you which directory you currently are in.
```bash
pwd
```
@ -707,7 +707,7 @@ pwd
</table>
### a. `ssh`
ssh (SSH client) is a program for logging into a remote machine and for executing commands on a remote machine.
ssh (SSH client) is a program for logging into and executing commands on a remote machine.
```bash
ssh user@host
```
@ -717,109 +717,109 @@ ssh -p port user@host
```
### b. `whoami`
Return current logged in username
Return current logged in username.
### c. `passwd`
Allows the current logged user to change his password
Allows the current logged user to change his password.
### d. `quota`
Shows what your disk quota is
Shows what your disk quota is.
```bash
quota -v
```
### e. `date`
Shows the current date and time
Shows the current date and time.
### f. `cal`
Shows the month's calendar
Shows the month's calendar.
### g. `uptime`
Shows current uptime
Shows current uptime.
### h. `w`
Displays who is online
Displays who is online.
### i. `finger`
Displays information about user
Displays information about user.
```bash
finger username
```
### j. `uname`
Shows kernel information
Shows kernel information.
```bash
uname -a
```
### k. `man`
Shows the manual for specified command
Shows the manual for specified command.
```bash
man command
```
### l. `df`
Shows disk usage
Shows disk usage.
### m. `du`
Shows the disk usage of the files and directories in filename (du -s give only a total)
Shows the disk usage of the files and directories in filename (du -s give only a total).
```bash
du filename
```
### n. `last`
Lists your last logins of specified user
Lists your last logins of specified user.
```bash
last yourUsername
```
### o. `ps`
Lists your processes
Lists your processes.
```bash
ps -u yourusername
```
### p. `kill`
Kills (ends) the processes with the ID you gave
Kills (ends) the processes with the ID you gave.
```bash
kill PID
```
### q. `killall`
Kill all processes with the name
Kill all processes with the name.
```bash
killall processname
```
### r. `top`
Displays your currently active processes
Displays your currently active processes.
### s. `bg`
Lists stopped or background jobs ; resume a stopped job in the background
Lists stopped or background jobs ; resume a stopped job in the background.
### t. `fg`
Brings the most recent job in the foreground.
### u. `ping`
Pings host and outputs results
Pings host and outputs results.
```bash
ping host
```
### v. `whois`
Gets whois information for domain
Gets whois information for domain.
```bash
whois domain
```
### w. `dig`
Gets DNS information for domain
Gets DNS information for domain.
```bash
dig domain
```
### x. `wget`
Downloads file
Downloads file.
```bash
wget file
```
@ -846,7 +846,7 @@ scp -P port user@host:directory/source_file target_file
# 2. Basic Shell Programming
This is first line that you will in bash script files called `shebang`. The shebang line in any script determines the script's ability to be executed like an standalone executable without typing sh, bash, python, php etc beforehand in the terminal.
The first line that you will write in bash script files is called `shebang`. This line in any script determines the script's ability to be executed like an standalone executable without typing sh, bash, python, php etc beforehand in the terminal.
```bash
#!/bin/bash
@ -854,21 +854,21 @@ This is first line that you will in bash script files called `shebang`. The sheb
## 2.1. Variables
Creating variable in bash is similar to other language. There are no data types. A variable in bash can contain a number, a character, a string of characters. You have no need to declare a variable, just assigning a value to its reference will create it.
Creating variables in bash is similar to other languages. There are no data types. A variable in bash can contain a number, a character, a string of characters, etc. You have no need to declare a variable, just assigning a value to its reference will create it.
Example:
```bash
str="hello world"
```
The above line creates a variable `str` and assigns "hello world" to it. Then the value of variable is retrieved by putting the `$` in the beginning of variable name.
The above line creates a variable `str` and assigns "hello world" to it. The value of variable is retrieved by putting the `$` in the beginning of variable name.
Example:
```bash
echo $str # hello world
```
Also like other languages bash has also arrays. An array is variable containing multiple values. There's no maximum limit on the size of array. Array in bash are zero based. The first element is indexed with element 0. There are several ways for creating arrays in bash. Which are given below.
Like other languages bash has also arrays. An array is variable containing multiple values. There's no maximum limit on the size of array. Array in bash are zero based. The first element is indexed with element 0. There are several ways for creating arrays in bash. Which are given below.
Examples:
```bash
@ -878,13 +878,13 @@ array[2] = val
array=([2]=val [0]=val [1]=val)
array(val val val)
```
To display a value at specific index use following syntax
To display a value at specific index use following syntax:
```bash
${array[i]} # where i is the index
```
One thing to note that if no index is supplied, array element 0 is assumed. To find out how many values there are in the array check following syntax
If no index is supplied, array element 0 is assumed. To find out how many values there are in the array use the following syntax:
```bash
${#array[@]}
@ -936,7 +936,7 @@ function say {
say "hello world!"
```
When you will run above example the `hello` function will output "world!". The above two functions `hello` and `say` are identical. The main difference is function `say`. This function, prints the first argument it receives. Arguments, within funtions, are treated in the same manner as arguments given to the script.
When you run the above example the `hello` function will output "world!". The above two functions `hello` and `say` are identical. The main difference is function `say`. This function, prints the first argument it receives. Arguments, within funtions, are treated in the same manner as arguments given to the script.
## 2.4. Conditionals