17 сент. 2013 г. · By standard it should be if [ "$time" -gt 300 ] && [ "$time" -lt 900 ] then mod=2 else mod=0 fi. In normal shell scripts you use [ and ] to ...

30 авг. 2010 г. · The right way: if [ -z ${var+x} ]; then echo "var is unset"; else echo "var is set to '$var'"; fi where ${var+x} is a parameter expansion which evaluates to

21 мар. 2015 г. · The correct way to use if is: mathtester=$(if [ 2 = 2 ]; then echo "equal"; else echo "not equal"; fi)

14 февр. 2019 г. · [ "$var" ] returns true if the length of $var is non-zero. If var is either unset or empty, it returns false.

28 окт. 2013 г. · If $VARIABLE is a string, then [ -n $VARIABLE ] is true if the length of $VARIABLE is non-zero. Also, [ -n $VARIABLE ] is equivalent with: [ $VARIABLE ] ,

13 апр. 2017 г. · You can use an if - else statement like this; if [ test ] then do something else do something else fi In your case if [ "$yourVariable" = "test" ] then while ...

13 янв. 2021 г. · You don't need the $ when checking if it is set and so: if [[ ! -v VAR ]]; then echo "unset" else echo "set: $VAR" fi.

26 окт. 2012 г. · A safer way to check is to enclose both sides in double quotes, ie if [ "$depth" -eq "0" ] ; this way, an unset variable ( $depth ) evaluates to "".

27 мая 2017 г. · The "right" way to check if a variable is set in bash looks like this: if [ -z ${var+x} ]; then echo "var is unset" else echo "var is set to '$var'" fi

15 мар. 2012 г. · You can use either " = " or " == " operators for string comparison in bash. The important factor is the spacing within the brackets.