First character of a variable in a shell script to uppercase?

问题

I have a shell script that starts unit tests for modules. I need the name of the module in all lowercase and with the first character uppercase. So far I have been doing it like this:

#!/bin/sh -x                                                                                                                                                                          
# z.B. getbrowser                                                                                                                                                                     
strModuleToTest=$1

# g                                                                                                                                                                                   
strModuleToTestUppercaseFirstletter=${strModuleToTest:0:1}
# etbrowser                                                                                                                                                                           
strModuleToTestUppercaseLastletters=${strModuleToTest:1}

# g -> G                                                                                                                                                                              
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/a/A}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/b/B}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/c/C}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/d/D}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/e/E}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/f/F}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/g/G}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/h/H}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/i/I}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/j/J}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/k/K}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/l/L}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/m/M}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/n/N}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/o/O}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/p/P}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/q/Q}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/r/R}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/s/S}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/t/T}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/u/U}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/v/V}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/w/W}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/x/X}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/y/Y}"
strModuleToTestUppercaseFirstletter="${strModuleToTestUppercaseFirstletter/z/Z}"

# Getbrowser
strModuleToTestUppercase=$strModuleToTestUppercaseFirstletter""$strModuleToTestUppercaseLastletters

What would be an easier way to set $strModuleToTestUppercase? I tried

strModuleToTestUppercase="${strModuleToTest[@]^}"

strModuleToTestUppercasesed="sed 's/\<./\u&/g' $strModuleToTest"

but without success.

回答1:

If:

s=somemodule

with bash v4+

echo ${s^}

This should work with a bit older bash versions (from Glenn):

echo $(tr a-z A-Z <<< ${s:0:1})${s:1}"

with zsh

echo ${(C)s}

with ash and coreutils

echo $(echo $s | cut -c1 | tr a-z A-Z)$(echo $s | cut -c2-)

with GNU sed

echo $s | sed 's/./\U&/'

with BSD sed

echo $s | sed '
  h;
  y/quvwxzdermatoglyphicsbfjkn/QUVWXZDERMATOGLYPHICSBFJKN/;
  G;
  s/\(.\)[^\n]*\n.\(.*\)/\1\2/;
'

with awk

echo $s | awk '{ print toupper(substr($0, 1, 1)) substr($0, 2) }'

with perl

echo $s | perl -nE 'say ucfirst'

with python

echo $s | python -c 'import sys; print sys.stdin.readline().rstrip().capitalize()'

with ruby

echo $s | ruby -e 'puts ARGF.read.capitalize'

Output in all cases

Somemodule

回答2:

You could use

strModuleToTestUpper=`sed 's/\(.\)/\U\1/' <<< "$strModuleToTest"`

Explanation

$.$ matches a single character
\U\1 replaces that character with an uppercase version
no /g means only the first match is processed.

回答3:

Is perl ok?

$ x=foobar
$ x=$(echo "$x" | perl -pe 's/^(.)/uc($1)/e')
$ echo $x
Foobar

来源：https://stackoverflow.com/questions/12420317/first-character-of-a-variable-in-a-shell-script-to-uppercase

标签

shell

unix

sed

awk