SHELL

bash if statement

and - &&
or - ||

# and example
if [ -r $1 ] && [ -s $1 ]
then
echo This file is useful.
fi

# or example
if [ $USER == 'bob' ] || [ $USER == 'andy' ]
then
ls -alh
else
ls
fi

bash if

#!/bin/bash

foo="qux"
bar="qux"

if [ "$foo" = "$bar" ]; then
    echo "The strings are equal."
else
    echo "The strings aren't equal."
fi

bash else if

if [ "$animal" == "penguin" ]; then
  echo "Hmmmmmm fish... Tux happy!"
elif [ "$animal" == "dolphin" ]; then
  echo "Pweetpeettreetppeterdepweet!"
else
  echo "*prrrrrrrt*"
fi

if TEST-COMMANDS; then
  CONSEQUENT-COMMANDS;
elif MORE-TEST-COMMANDS; then
  MORE-CONSEQUENT-COMMANDS;
else
  ALTERNATE-CONSEQUENT-COMMANDS;
fi

bash if else

# Basic syntax
if [[ condition_1 ]]; then
	echo "Code to execute if condition_1 is true"
elif [[ condition_2 ]]; then
	echo "Code to execute if condition_1 is false and condition_2 is true"
else
	echo "Code to execute if condition_1 and condition_2 are false"
fi

# Note, the syntax for the one-line equivalent is:
if [[ condition_1 ]]; then echo "Code to execute if condition_1 is true"; elif [[ condition_2 ]]; then echo "Code to execute if condition_1 is false and condition_2 is true"; else echo "Code to execute if condition_1 and condition_2 are false"; fi


# Note to self, see this link for more on bash operators and [ ] vs [[ ]]:
# 	https://tldp.org/LDP/abs/html/comparison-ops.html

if and if bash

if [ "${STATUS}" != 200 ] && [ "${STRING}" != "${VALUE}" ]; then

if statement in shell script

  if [ "$result" == "1" ]
    then 
      echo "test" >> /home/samurai/test.txt
    fi
    

    
    if [[ "$result" -eq "1" ]]
    then 
      echo "test" >> /home/samurai/test.txt
    fi
    

if else bash shell script

if [[ some condition ]]; then
  do_this
elif [[ another condition ]]; then
  do_that_a
elif [[ yet another condition]]; then
  do_that_b
else
  do_that_default_thing
fi

bash if statement

Operator			Description
! EXPRESSION			The EXPRESSION is false.
-n STRING			The length of STRING is greater than zero.
-z STRING			The lengh of STRING is zero (ie it is empty).
STRING1 = STRING2		STRING1 is equal to STRING2
STRING1 != STRING2		STRING1 is not equal to STRING2
INTEGER1 -eq INTEGER2		INTEGER1 is numerically equal to INTEGER2
INTEGER1 -gt INTEGER2		INTEGER1 is numerically greater than INTEGER2
INTEGER1 -lt INTEGER2		INTEGER1 is numerically less than INTEGER2
-d FILE				FILE exists and is a directory.
-e FILE				FILE exists.
-r FILE				FILE exists and the read permission is granted.
-s FILE				FILE exists and it's size is greater than zero (ie. it is not empty).
-w FILE				FILE exists and the write permission is granted.
-x FILE				FILE exists and the execute permission is granted.

bash if

nome=tiago
## with SPACE between variable and comparation
if [ $nome == 'tiago' ] ;
then
    echo "hello Tiago"
fi

bash ifelse

# you can use it if you want but it isn't very accurate
# as of best practices and such 

for DB in $( sudo mysql -e 'show databases' -s --skip-column-names ) ; 
	do 
		if [ $DB == 'information_schema' ] || [ $DB == 'performance_schema' ]; 
        	then echo 'warning' ; 
        else 
        	echo "success $DB";
        fi 
        
    done

linux bash if else

if [[ condition ]]
then
  <execute command>
else
  <execute another command>
fi

bash negate if

if [[ $? -ne 0 ]]; then       # -ne: not equal

if ! [[ $? -eq 0 ]]; then     # -eq: equal

if [[ ! $? -eq 0 ]]; then

if statement bash

#!/bin/bash
# Basic if statement
if [ $1 -gt 100 ]
then
echo Hey that's a large number.
pwd
fi

If else Bash

if TEST-COMMAND
then
  STATEMENTS1
else
  STATEMENTS2
fi

linux bash if else

if [[ condition ]]
then
  <execute command>
else
  <execute another command>
fi

bash if else if

if [[ TEST-COMMAND ]]
then
  STATEMENTS1
else
  STATEMENTS2
fi

Bash if statement

if first-test-commands; then
  consequent-commands;
[elif more-test-commands; then
  more-consequents;]
[else alternate-consequents;]
fi