#!/bin/bash
# use chmod +x to give executable permission to run this script
echo "Hi there, SUP ?" #this will print to the screen
echo "jkdsfjdsjf #fjdfjklsd"
echo fdsjfsdjlkf #jvjkdflksdfkjl
name=tea
echo "the word is $name conatains ${#name} chars"
echo $(( 2#111 )) #count len of string
echo "Hey there"; echo "you there " #terminating the command
var=1
if [ "$var" -gt 0 ]; then echo "YES"; else echo "NO"
fi #if-else loop in bash
# cp -R /path/to/source/ . command to copy some content to the current folder
colors="red green blue"
echo $colors
for col in $colors
do #for and do loop in bash
echo $col
done
for col in "$colors"
do
echo $col #for and do loop in bash
done
for col in '$colors'
do
echo $col #for and do loop in bash
done
let "y=((x=20, 10/2))"
echo $y
var=DSLCoNnEctiOn
echo ${var,}
echo ${var,,}
echo ${var^}
echo ${var^^}
echo "\"Linux is awesome\""
# ls --help | grep "\-l" to use "" in grep
let val=500/2
val2=`echo $val`
echo $val2
var=20
if [ "$var" -gt 15 ]
then : #null operator
else
echo $var
fi
# touch file.ext to create a new file
# echo "something new" > file.ext to append to the empty file
# echo "somrthing newer" >> file.ext to apppend to a file with some existing text
# : > file.txt to clean all the contents of a file
# : >> file.txt to create a file with fail-save option
var=10
if [ "$var" != 0 ]
then
echo "NOT"
else
echo "YES"
fi
let var=100*10
let var2=100**3
echo "$var $var2"
# rm filename* deletes everything that starts with filename
var=10
echo $(( var2 = var1<20?1:0))
colors=(red green blue) # an array in bash
var=1
(var=2;) # var = 1
echo \${test1,test2,test3}\$
echo {1..10} # loop
var1=1
var2=2
{
var1=11
var2=12 # updated values will be 11 and 12
}
# || OR
# && AND
# - + % / same as in any other programing language
# cd ~ home directory
echo ~+
echo ~-
unset var # unset var duh.."""
read var # to read input
echo $var
"""
for var in 1 2 3
do
echo $var
done
echo $? #return exit value
# $# no of arg passed
"""
read var
if [ "$var" -gt 0 ]
then
if [ "$var" -lt 1000**1000 ]
then
if [ "$var" -gt 1]
echo "Between 1 and 10"
fi
fi
elif [ "$var" -eq 0 ]
echo "Zero it is"
else
echo "It is a neg"
fi
"""
#!/bin/bash
var=/home/priyanshu/Desktop/Dump/bash_scripting/third.sh
if [[ -e $var ]]
then
echo "Files exists"
else
echo "Doesn't exist"
fi
(( 2 > 1 ))
echo "Exit status is $?"
(( 2 - 2 ))
echo "Exit status is $?"
# ! files as a opeartor
# -r true if user has permission to read
# -w true if user has permission to write
# -x true if user has permission to execute
# -f true if given file is not a dir
# -s true if given is not empty
# -e " " if file exists
echo "$$" # PID
for var in {0..5}
do
echo "BASH_VERSINFO[$var] = ${BASH_VERSINFO[$var]}"
done
ROOT_UID=0
echo -n "YOU ARE: "
if [ "$UID" -eq "$ROOT_UID" ]
then
echo "root, YOUR \$UID = $UID"
else
echo "user, YOUR \UID = $UID"
fi
someFunction()
{
echo "Function name is $FUNCNAME"
}
someFunction
echo "Outside, \$FUNCNAME = $FUNCNAME"
declare -r PI=3.1415926
printf "Value upto second decimal of PI is %1.2f\n" $PI