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Bash Scripting Examples for String and Numeric Comparisons

Learn how to perform string and numeric comparisons in Bash scripts with detailed examples and explanations. Improve your scripting skills now!

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Bash Scripting Examples for String and Numeric Comparisons

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  1. Experiment No 8 Presented by, Mr. SatishPise

  2. Test command string comparison

  3. Example 1:testing string equality using = #cat > testdemo #!/bin/bash # testing string equality testuser=rich if [ $USER = $testuser ] then echo "Welcome $testuser" fi # shtestdemo

  4. Example 2:testing string using != # cat > testdemo2 #!/bin/bash # testing string equality testuser=baduser if [ $USER != $testuser ] then echo "This isn’t $testuser" else echo "Welcome $testuser" fi # shtestdemo2

  5. Example 3ng string comparisons # cat > badtest #!/bin/bash # mis-using string comparisons val1=baseball val2=hockey if [ $val1 > $val2 ] then echo "$val1 is greater than $val2" else echo "$val1 is less than $val2" fi $ shbadtest $ ls -l hockey

  6. Example 4:testing string sort order $ cat > test9b #!/bin/bash # testing string sort order val1=Testing val2=testing if [ $val1 \> $val2 ] then echo "$val1 is greater than $val2" else echo "$val1 is less than $val2" fi $ sh test9b Testing is less than testing $ sort testfile

  7. Numeric comparisons

  8. Example 1:using numeric test comparisons # cat > test5 #!/bin/bash # using numeric test comparisons val1=10 val2=11 if [ $val1 -gt 5 ] then echo "The test value $val1 is greater than 5" fi if [ $val1 -eq $val2 ] then echo "The values are equal" else echo "The values are different" fi echo The first test condition: if [ $val1 -gt 5 ] echo tests if the value of the variable val1 is greater than 5. The second test condition: if [ $val1 -eq $val2 ] echo There is a limitation to the test numeric conditions though. Try this script: #sh test5

  9. Example 2: $ cat > test6 #!/bin/bash # testing floating point numbers val1=` echo "scale=4; 10 / 3 " | bc` echo "The test value is $val1" if [ $val1 -gt 3 ] then echo "The result is larger than 3" fi $ sh test6

  10. Testing File Comparison

  11. Checking directories Example 1: # cat > test11 #!/bin/bash if [ -d $HOME ] then echo "Your HOME directory exists" cd $HOME ls -a else echo "There’s a problem with your HOME directory" fi #sh test11

  12. Checking for a file $ cat > test13 #!/bin/bash # check if a file if [ -e $HOME ] then echo "The object exists, is it a file?" if [ -f $HOME ] then echo "Yes, it’s a file!" else echo "No, it’s not a file!" if [ -f $HOME/.bash history ] then echo "But this is a file!" fi fi else echo "Sorry, the object doesn’t exist" fi $ sh test13

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