String Manipulation 字串處理

字串長度

my_string="abhishek"
echo "length is ${#my_string}"

Using expr

str="my string"
length=$(expr length "$str")
echo "Length of my string is $length"

Using awk

echo "my string" | awk '{print length}'

Using wc

str="my string"
length=$(echo -n "my string" | wc -m)
echo "Length of my string is $length"

字串比對

Using wildcards

#!/bin/bash

STR='GNU/Linux is an operating system'
SUB='Linux'
if [[ "$STR" == *"$SUB"* ]]; then
  echo "It's there."
fi

Using case

#!/bin/bash

STR='GNU/Linux is an operating system'
SUB='Linux'

case $STR in

  *"$SUB"*)
    echo -n "It's there."
    ;;
esac

Using Regex

#!/bin/bash

STR='GNU/Linux is an operating system'
SUB='Linux'

if [[ "$STR" =~ .*"$SUB".* ]]; then
  echo "It's there."
fi

Using Grep

#!/bin/bash

STR='GNU/Linux is an operating system'
SUB='Linux'

if grep -q "$SUB" <<< "$STR"; then
  echo "It's there"
fi

字串合併

str1="hand"
str2="book"
str3=$str1$str2

字元提取

foss="Fedora is a free operating system"
echo ${foss:0:6}

字元取代

foss="Fedora is a free operating system"
echo ${foss/Fedora/Ubuntu}