uppercase first character in a variable with bash

Question

I want to uppercase just the first character in my string with bash.

foo=\"bar\";

//uppercase first character

echo $foo;

should print \"B

Answer 1

To capitalize first word only:

foo='one two three'
foo="${foo^}"
echo $foo

One two three

---

To capitalize every word in the variable:

foo="one two three"
foo=( $foo ) # without quotes
foo="${foo[@]^}"
echo $foo

One Two Three

---

(works in bash 4+)

Answer 2

This one worked for me:

Searching for all *php file in the current directory , and replace the first character of each filename to capital letter:

e.g: test.php => Test.php

for f in *php ; do mv "$f" "$(\sed 's/.*/\u&/' <<< "$f")" ; done

Answer 3

$ foo="bar";
$ foo=`echo ${foo:0:1} | tr  '[a-z]' '[A-Z]'`${foo:1}
$ echo $foo
Bar

Answer 4

It can be done in pure bash with bash-3.2 as well:

# First, get the first character.
fl=${foo:0:1}

# Safety check: it must be a letter :).
if [[ ${fl} == [a-z] ]]; then
    # Now, obtain its octal value using printf (builtin).
    ord=$(printf '%o' "'${fl}")

    # Fun fact: [a-z] maps onto 0141..0172. [A-Z] is 0101..0132.
    # We can use decimal '- 40' to get the expected result!
    ord=$(( ord - 40 ))

    # Finally, map the new value back to a character.
    fl=$(printf '%b' '\'${ord})
fi

echo "${fl}${foo:1}"

Answer 5

One way with bash (version 4+):

foo=bar
echo "${foo^}"

prints:

Bar

Answer 6

This works too...

FooBar=baz

echo ${FooBar^^${FooBar:0:1}}

=> Baz

FooBar=baz

echo ${FooBar^^${FooBar:1:1}}

=> bAz

FooBar=baz

echo ${FooBar^^${FooBar:2:2}}

=> baZ

And so on.

Sources:

• Bash Manual: Shell Parameter Expansion
• Full Bash Guide: Parameters
• Bash Hacker's Wiki Parameter Expansion

Inroductions/Tutorials:

• Cyberciti.biz: 8. Convert to upper to lower case or vice versa
• Opensource.com: An introduction to parameter expansion in Bash