Bash: Return a string from bash function [duplicate]

The return statement used by bash is used to return a numeric value as a status code to be retrieved through $? by the calling function. You can not return a string. See also

• Returning Values from Bash Functions
• How to return a string value from a Bash function

You can either use a special global variable as proposed by @konsolebox, or echo the return value inside your function, and use command substitution when calling the function:

makeName(){    echo "$fileName.$1.log"}echo -n "Enter fileName:"read fileNamename1=$(makeName "type1")name2=$(makeName "type2")echo $name1echo $name2

[UPDATE]

The updated question shows that you intend to read yet another value inside the makeName function, while the function also intends to echo some prompt for the user. So the command substitution approach will not work in that case - you need to use a global variable, like

makeName() {    echo -n "Enter Ext: "    read ext    __="$fileName.$1.$ext.log"}echo -n "Enter fileName:"read fileNamemakeName "type1" ; name1=${__}makeName "type2" ; name2=${__}echo $name1echo $name2

$ ./sample.sh Enter fileName:filenameEnter Ext: ext1Enter Ext: ext2filename.type1.ext1.logfilename.type2.ext2.log

Yet better, for cleaner code and to avoid using global variables inside your function, you could use the approach described at Returning Values from Bash Functions and pass the name of the return variable as parameter, and ideally also pass the fileName as parameter:

makeName() {    local  __type=$1    local  __fileName=$2    local  __resultvar=$3    local ext    local myresult    echo -n "Enter Ext: "    read ext    myresult="$__fileName.$__type.$ext.log"    eval $__resultvar="'$myresult'"}echo -n "Enter fileName:"read fileNamemakeName "type1" $fileName theResult ; name1=${theResult}makeName "type2" $fileName theResult ; name2=${theResult}echo $myresultecho $name1echo $name2

Side Note: See Why should eval be avoided in Bash, and what should I use instead? for a discussion why eval should be avoided. When using bash version 3.1 or higher, you can use printf instead of eval:

...printf -v "$__resultvar" '%s' "$myresult"...

And, finally, with bash 4.3 or higher, we can assign the nameref attribute to a variable using declare -n, so that the variable is effectively a reference to another variable:

...declare -n myresult=$3myresult="$__fileName.$__type.$ext.log"...

Better way is to pick a general variable you could always use. Example:

makeName() {    __="$fileName.$1.log"}    echo -n "Enter fileName:"read fileNamemakeName "type1"name1=$__makeName "type2"name2=$__echo "$name1"echo "$name2"

Summoning subshells just to get a value from a function is really inefficient and slow.

Just replace return with echo:

makeName(){    echo "Enter Ext: " >&2    read ext    echo "$fileName.$1.$ext.log"}