文件&字符串&算术等测试操作,主要方便调试判断的使用。 #文件测试操作-d FILE_NAM # TrueifFILE_NAM is a directory-e FILE_NAM # TrueifFILE_NAM exists-f FILE_NAM # TrueifFILE_NAM existsandis a regular file-r FILE_NAM # TrueifFILE_NAM is readabl...
echo "Array does not contain $search_value" exit 1 fi Output 1 2 3 Array contains cherry Using for Loop To determine if a Bash array contains a value: Use the for loop to iterate over the array. In each iteration, use the if-else block to check if the specified value exists in...
last = (last *10) + _rl_digit_value (spec[i]); }elseif(spec[i] =='$') { i++; last ='$'; }#if0elseif(!spec[i] || spec[i] ==':')/* check against `:' because there could be a modifier separator */#elseelse/* csh seems to allow anything to terminate the word spe...
test -f /etc/fstab ## true if a regular file test -h /etc/rc.local ## true if a symbolic link [ -x "$HOME/bin/hw" ] ## true if you can execute the file [[ -s $HOME/bin/hw ]] ## true if the file exists and is not empty 整数测试 整数之间的比较使用-eq、-ne、-gt...
- Test if the specified variable has a [n]on-empty value: [[ -n $variable ]] - Test if the specified variable has an empty value: [[ -z $variable ]] - Test if the specified [f]ile exists: [[ -f path/to/file ]] - Test if the specified [d]irectory exists: ...
# bash check if directory exists if [ -d $directory ]; then echo "Directory exists" else echo "Directory does not exists" fi 1. 2. 3. 4. 5. 6. 7. 8. 9. 9.2. Nested if/else #!/bin/bash # Declare variable choice and assign value 4 ...
How to check if a directory exists? How to check if a command succeeds or failed? How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if sta...
check if value is bla or not phone_missing=false if [ "$phone_missing" != false ]; then echo "phone_missing is not 'false' (but may be non-true, too)" fi if [ "$phone_missing" == true ]; then echo "phone_missing is true." fi check if variable exists if [[ "$phone_miss...
As you can see the filemath.shexists! Most of the time when you’re writing bash scripts you won’t be comparing two raw values or trying to find something out about one raw value, instead you’ll want to create a logical statement about a value contained in a variable. Variables behav...
Checking if a variable exists ([[ -v varname ]]): Yes, this is possibly a killer argument, but consider the programming style of always setting variables, so you don't need to check if they exist.Are empty string comparisons any special?Of...