How to uppercase the command line argument?

I searched SO and found that to uppercase a string following would work

str="Some string"
echo ${str^^}

But I tried to do a similar thing on a command-line argument, which gave me the following error

Tried

#!/bin/bash
             ## Output
echo ${1^^}  ## line 3: ${1^^}: bad substitution
echo {$1^^}  ## No error, but output was still smaller case i.e. no effect

How could we do this?

Answers:

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Method 1

The syntax str^^ which you are trying is available from Bash 4.0 and above. Perhaps yours is an older version (or you ran the script with sh explicitly):

Try this:

str="Some string"
printf '%sn' "$str" | awk '{ print toupper($0) }'

Method 2

echo "lowercase" | tr a-z A-Z

Output:

LOWERCASE

Method 3

Be careful with tr unless A-Z is all you use. For other locales even ‘[:lower:]’ ‘[:upper:]’ fails, only awk’s toupper and bash (v4+) works

$ str="abcåäö"
$ echo "$str"|tr '/a-z/' '/A-Z/'
ABCåäö
$ echo "$str"|LC_ALL=sv_SE tr '[:lower:]' '[:upper:]'
ABCåäö
$ echo "$str"|awk '{print toupper($0)}'
ABCÅÄÖ
$ echo ${str^^} # Bash 4.0 and later
ABCÅÄÖ
$ STR="ABCÅÄÖ"
$ echo ${STR,,}
abcåäö

Method 4

Alternatively, you could switch to ksh or zsh which have had case conversion support for decades (long before bash‘s ${var^^} added in 4.0), though with a different syntax:

#! /bin/ksh -
typeset -u upper="$1"
printf '%sn' "$upper"

(also works with zsh; note that in pdksh/mksh, that only works for ASCII letters).

With zsh, you can also use the U parameter expansion flag:

#! /bin/zsh -
printf '%sn' "${(U)1}"

POSIXLY, you can use:

awk 'BEGIN{print toupper(ARGV[1])}' "$1"

There’s also:

printf '%sn' "$1" | tr '[:lower:]' '[:upper:]'

But in a few implementations, including GNU tr, that only works for single-byte characters (so in UTF-8 locales, only on ASCII letters).

Method 5

If someone is still getting error trying ${str^^}, you can try python -c or perl It is likely because bash version is lower than 4.

But, so far bash 4 or over is working swiftly with the existing solution.

L2U="I will be upper"

Using python -c in bash

python -c "print('$L2U'.upper())"
I WILL BE UPPER

Similarly it also can be used to capitalise with:

service="bootup.sh on home"
python -c "print('$service'.capitalize())"
Bootup.sh on home

Using perl

echo $L2U | perl -ne 'print "U$_"'
I WILL BE UPPER

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0