I just shortly describe some Linux shell script and shell commands.Hopefully, it will help you to file edit, make, delete directory operations, grep, pipeline and lots of stuff to your Linux/Mac terminal.

1. Shell Commands
and
Shell Scripts
Presented By:
Nazmul Hyder
ID- 011 131 085

2. Shell Command
Identity and Manual
Command Description
$uame Linux will tell you his name to you
$whoami If you want to know your name
$man uname For each command manual

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Editors
Command Description
$ kwrite File write
$gedit File Edit
$vi

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File Listing
Command Description
$ls -a Do not hide entries starting with.
$ls -h Print size in human readable format
$ls -l Use a long listing format
$ls -s Sort by file size

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Directory Operations
Command Description
$pwd If u want to see your current directory
$cd “directory name” To change the directory
$mkdir “directory name” Create a new directory
$rmdir “directory name” Remove an empty directory
$rmdir -r “directory name” Remove directory with file

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File Operations
Command Description
$cp “file” “copyfile.txt” Copy file
$rm “file.txt” To remove file
$mv “file.txt “ “directory name” Create a new directory
$file -i “file name” To know the file type
$file -v “file name” Print the version of the file
$cat “file1” “file2” To concat files and print on the
standard output

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File Viewing
Command Description
$echo “some text” You can a line of text in the shell
$more file.txt It uses for the Spacebar and the B key for
the forward and backward navigation
$less “file.txt” Less allows forward and backward
movement using arrow keys
$head filename To see the first 10 contents of the file
$tail filename To see the last 10 contents of the file

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File Viewing
Command Description
$filename -n To print the line number of the file
$sort file1 file2 To write the sorted concatenation of all
the file and standard output
$wc filename Print bytes,words,total lines
$wc -l or -w You can see specific

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Piping and Grep
Command Description
$head -10 a.txt | tail -5 To see 5-10 number lines of a file
$grep “a” file.txt Print lines which contains “a”
$grep -i For case insensitive search
$grep -c Count total matches
$grep -n Display the line number of matches

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Grep
Command Description
$grep -E [^F] filename Anything except capital F
$grep -E [$a] filename Anything that ends with a
$grep -E [a-zA-Z] filename Anything that contains small a to z and
capital A to Z

11. Shell Script
Advantage of shell script :
● It take input from user , file and output them on screen.
● Useful to create own commands.
● Save time.

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Write and Execute :
● We can use any editor to write the shell script.
● The extension is .sh
● Two thing you can need to do before execute file
○ Chmod +x script_name “set execute permission for your script”
○ ./script_name “execute script”

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Shell Script Examples
Arithmetic if-else Case
#!/bin/bash
expr 1 + 1
expr 1 ‐1
expr 1 * 1
expr 1 / 1
var=`expr 1 + 1`
x=1
x=`expr $x + 1`
#!/bin/bash
echo "Enter first number "
read num1
echo "Enter second number"
read num2
if [ $num1 ‐gt $num2 ] ; then
echo
"$num1 is greater than $num2"
elif [ $num1 ‐lt $num2 ] ; then
echo "$num1 is less than $num2"
else
echo "$num1 and $num2 are equal"
fi
#!/bin/sh
echo “Is it morning? Please answer
yes or no”
read timeofday
case “$timeofday” in
yes) echo “Good Morning”;;
no ) echo “Good Afternoon”;;
y ) echo “Good Morning”;;
n ) echo “Good Afternoon”;;
* ) echo “Sorry, answer not
recognized”;;
esac

14. Thank You