The are various ways:
POSIX standard
tr
$ echo "$a" | tr '[:upper:]' '[:lower:]'
hi all
AWK
$ echo "$a" | awk '{print tolower($0)}'
hi all
Non-POSIX
You may run into portability issues with the following examples:
Bash 4.0
$ echo "${a,,}"
hi all
sed
$ echo "$a" | sed -e 's/\(.*\)/\L\1/'
hi all
# this also works:
$ sed -e 's/\(.*\)/\L\1/' <<< "$a"
hi all
Perl
$ echo "$a" | perl -ne 'print lc'
hi all
Bash
lc(){
case "$1" in
[A-Z])
n=$(printf "%d" "'$1")
n=$((n+32))
printf \\$(printf "%o" "$n")
;;
*)
printf "%s" "$1"
;;
esac
}
word="I Love Bash"
for((i=0;i<${#word};i++))
do
ch="${word:$i:1}"
lc "$ch"
done
Note: YMMV on this one. Doesn't work for me (GNU bash version 4.2.46 and 4.0.33 (and same behaviour 2.05b.0 but nocasematch is not implemented)) even with using shopt -u nocasematch;
. Unsetting that nocasematch causes [[ "fooBaR" == "FOObar" ]] to match OK BUT inside case weirdly [b-z] are incorrectly matched by [A-Z]. Bash is confused by the double-negative ("unsetting nocasematch")! :-)
In Bash 4:
To lowercase
$ string="A FEW WORDS"
$ echo "${string,}"
a FEW WORDS
$ echo "${string,,}"
a few words
$ echo "${string,,[AEIUO]}"
a FeW WoRDS
$ string="A Few Words"
$ declare -l string
$ string=$string; echo "$string"
a few words
To uppercase
$ string="a few words"
$ echo "${string^}"
A few words
$ echo "${string^^}"
A FEW WORDS
$ echo "${string^^[aeiou]}"
A fEw wOrds
$ string="A Few Words"
$ declare -u string
$ string=$string; echo "$string"
A FEW WORDS
Toggle (undocumented, but optionally configurable at compile time)
$ string="A Few Words"
$ echo "${string~~}"
a fEW wORDS
$ string="A FEW WORDS"
$ echo "${string~}"
a FEW WORDS
$ string="a few words"
$ echo "${string~}"
A few words
Capitalize (undocumented, but optionally configurable at compile time)
$ string="a few words"
$ declare -c string
$ string=$string
$ echo "$string"
A few words
Title case:
$ string="a few words"
$ string=($string)
$ string="${string[@]^}"
$ echo "$string"
A Few Words
$ declare -c string
$ string=(a few words)
$ echo "${string[@]}"
A Few Words
$ string="a FeW WOrdS"
$ string=${string,,}
$ string=${string~}
$ echo "$string"
A few words
To turn off a declare
attribute, use +
. For example, declare +c string
. This affects subsequent assignments and not the current value.
The declare
options change the attribute of the variable, but not the contents. The reassignments in my examples update the contents to show the changes.
Edit:
Added "toggle first character by word" (${var~}
) as suggested by ghostdog74.
Edit: Corrected tilde behavior to match Bash 4.3.
string="łódź"; echo ${string~~}
will return "ŁÓDŹ", but echo ${string^^}
returns "łóDź". Even in LC_ALL=pl_PL.utf-8
. That's using bash 4.2.24.
en_US.UTF-8
. It's a bug and I've reported it.
echo "$string" | tr '[:lower:]' '[:upper:]'
. It will probably exhibit the same failure. So the problem is at least partly not Bash's.
echo "Hi All" | tr "[:upper:]" "[:lower:]"
tr
doesn't work for me for non-ACII characters. I do have correct locale set and locale files generated. Have any idea what could I be doing wrong?
[:upper:]
needed?
[:upper:]
is needed.
tr:
a="$(tr [A-Z] [a-z] <<< "$a")"
AWK:
{ print tolower($0) }
sed:
y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/
a="$(tr [A-Z] [a-z] <<< "$a")"
looks easiest to me. I am still a beginner...
sed
solution; I've been working in an environment that for some reason doesn't have tr
but I've yet to find a system without sed
, plus a lot of the time I want to do this I've just done something else in sed
anyway so can chain the commands together into a single (long) statement.
tr [A-Z] [a-z] A
, the shell may perform filename expansion if there are filenames consisting of a single letter or nullgob is set. tr "[A-Z]" "[a-z]" A
will behave properly.
sed
tr [A-Z] [a-z]
is incorrect in almost all locales. for example, in the en-US
locale, A-Z
is actually the interval AaBbCcDdEeFfGgHh...XxYyZ
.
I know this is an oldish post but I made this answer for another site so I thought I'd post it up here:
UPPER -> lower: use python:
b=`echo "print '$a'.lower()" | python`
Or Ruby:
b=`echo "print '$a'.downcase" | ruby`
Or Perl:
b=`perl -e "print lc('$a');"`
Or PHP:
b=`php -r "print strtolower('$a');"`
Or Awk:
b=`echo "$a" | awk '{ print tolower($1) }'`
Or Sed:
b=`echo "$a" | sed 's/./\L&/g'`
Or Bash 4:
b=${a,,}
Or NodeJS:
b=`node -p "\"$a\".toLowerCase()"`
You could also use dd
:
b=`echo "$a" | dd conv=lcase 2> /dev/null`
lower -> UPPER:
use python:
b=`echo "print '$a'.upper()" | python`
Or Ruby:
b=`echo "print '$a'.upcase" | ruby`
Or Perl:
b=`perl -e "print uc('$a');"`
Or PHP:
b=`php -r "print strtoupper('$a');"`
Or Awk:
b=`echo "$a" | awk '{ print toupper($1) }'`
Or Sed:
b=`echo "$a" | sed 's/./\U&/g'`
Or Bash 4:
b=${a^^}
Or NodeJS:
b=`node -p "\"$a\".toUpperCase()"`
You could also use dd
:
b=`echo "$a" | dd conv=ucase 2> /dev/null`
Also when you say 'shell' I'm assuming you mean bash
but if you can use zsh
it's as easy as
b=$a:l
for lower case and
b=$a:u
for upper case.
a
contains a single quote, you have not only broken behavior, but a serious security problem.
Bash 5.1 provides a straight forward way to do this with the L
parameter transformation:
${var@L}
So for example you can say:
$ v="heLLo"
$ echo "${v@L}"
hello
You can also do uppercase with U
:
$ v="hello"
$ echo "${v@U}"
HELLO
And uppercase the first letter with u
:
$ v="hello"
$ echo "${v@u}"
Hello
${v^^}
and ${v,,}
already exist.
In zsh:
echo $a:u
Gotta love zsh!
echo ${(C)a} #Upcase the first char only
Using GNU sed
:
sed 's/.*/\L&/'
Example:
$ foo="Some STRIng";
$ foo=$(echo "$foo" | sed 's/.*/\L&/')
$ echo "$foo"
some string
Pre Bash 4.0
Bash Lower the Case of a string and assign to variable
VARIABLE=$(echo "$VARIABLE" | tr '[:upper:]' '[:lower:]')
echo "$VARIABLE"
echo
and pipes: use $(tr '[:upper:]' '[:lower:]' <<<"$VARIABLE")
For the Bash command line and depending on locale and international letters, this might work (assembled from the answers from others):
$ echo "ABCÆØÅ" | python -c "print(open(0).read().lower())"
abcæøå
$ echo "ABCÆØÅ" | sed 's/./\L&/g'
abcæøå
$ export a="ABCÆØÅ" | echo "${a,,}"
abcæøå
Whereas these variations might NOT work:
$ echo "ABCÆØÅ" | tr "[:upper:]" "[:lower:]"
abcÆØÅ
$ echo "ABCÆØÅ" | awk '{print tolower($1)}'
abcÆØÅ
$ echo "ABCÆØÅ" | perl -ne 'print lc'
abcÆØÅ
$ echo 'ABCÆØÅ' | dd conv=lcase 2> /dev/null
abcÆØÅ
echo "ABCÆØÅ" | ruby -pe '$_.downcase!'
work correctly?
You can try this
s="Hello World!"
echo $s # Hello World!
a=${s,,}
echo $a # hello world!
b=${s^^}
echo $b # HELLO WORLD!
https://i.stack.imgur.com/QSM2h.png
ref : http://wiki.workassis.com/shell-script-convert-text-to-lowercase-and-uppercase/
Simple way
echo "Hi all" | awk '{ print tolower($0); }'
echo 'Đêm lưu trú năm nay' | awk '{ print tolower($0); }'
=> đêm lưu trú năm nay
, and echo 'ЛШТШФУМ АЩЬФ' | awk '{ print tolower($0); }'
=> лштшфум ащьф
For a standard shell (without bashisms) using only builtins:
uppers=ABCDEFGHIJKLMNOPQRSTUVWXYZ
lowers=abcdefghijklmnopqrstuvwxyz
lc(){ #usage: lc "SOME STRING" -> "some string"
i=0
while ([ $i -lt ${#1} ]) do
CUR=${1:$i:1}
case $uppers in
*$CUR*)CUR=${uppers%$CUR*};OUTPUT="${OUTPUT}${lowers:${#CUR}:1}";;
*)OUTPUT="${OUTPUT}$CUR";;
esac
i=$((i+1))
done
echo "${OUTPUT}"
}
And for upper case:
uc(){ #usage: uc "some string" -> "SOME STRING"
i=0
while ([ $i -lt ${#1} ]) do
CUR=${1:$i:1}
case $lowers in
*$CUR*)CUR=${lowers%$CUR*};OUTPUT="${OUTPUT}${uppers:${#CUR}:1}";;
*)OUTPUT="${OUTPUT}$CUR";;
esac
i=$((i+1))
done
echo "${OUTPUT}"
}
${var:1:1}
are a Bashism.
In bash 4 you can use typeset
Example:
A="HELLO WORLD"
typeset -l A=$A
bash
which is 'stuck' at 3.2.57(1)... (Note: aye, I'm aware we can always install a more recent bash
from homebrew
...)
Regular expression
I would like to take credit for the command I wish to share but the truth is I obtained it for my own use from http://commandlinefu.com. It has the advantage that if you cd
to any directory within your own home folder that is it will change all files and folders to lower case recursively please use with caution. It is a brilliant command line fix and especially useful for those multitudes of albums you have stored on your drive.
find . -depth -exec rename 's/(.*)\/([^\/]*)/$1\/\L$2/' {} \;
You can specify a directory in place of the dot(.) after the find which denotes current directory or full path.
I hope this solution proves useful the one thing this command does not do is replace spaces with underscores - oh well another time perhaps.
prename
from perl
: dpkg -S "$(readlink -e /usr/bin/rename)"
gives perl: /usr/bin/prename
Converting case is done for alphabets only. So, this should work neatly.
I am focusing on converting alphabets between a-z from upper case to lower case. Any other characters should just be printed in stdout as it is...
Converts the all text in path/to/file/filename within a-z range to A-Z
For converting lower case to upper case
cat path/to/file/filename | tr 'a-z' 'A-Z'
For converting from upper case to lower case
cat path/to/file/filename | tr 'A-Z' 'a-z'
For example,
filename:
my name is xyz
gets converted to:
MY NAME IS XYZ
Example 2:
echo "my name is 123 karthik" | tr 'a-z' 'A-Z'
# Output:
# MY NAME IS 123 KARTHIK
Example 3:
echo "my name is 123 &&^&& #@$#@%%& kAR2~thik" | tr 'a-z' 'A-Z'
# Output:
# MY NAME IS 123 &&^&& #@0@%%& KAR2~THIK
Many answers using external programs, which is not really using Bash
.
If you know you will have Bash4 available you should really just use the ${VAR,,}
notation (it is easy and cool). For Bash before 4 (My Mac still uses Bash 3.2 for example). I used the corrected version of @ghostdog74 's answer to create a more portable version.
One you can call lowercase 'my STRING'
and get a lowercase version. I read comments about setting the result to a var, but that is not really portable in Bash
, since we can't return strings. Printing it is the best solution. Easy to capture with something like var="$(lowercase $str)"
.
How this works
The way this works is by getting the ASCII integer representation of each char with printf
and then adding 32
if upper-to->lower
, or subtracting 32
if lower-to->upper
. Then use printf
again to convert the number back to a char. From 'A' -to-> 'a'
we have a difference of 32 chars.
Using printf
to explain:
$ printf "%d\n" "'a"
97
$ printf "%d\n" "'A"
65
97 - 65 = 32
And this is the working version with examples. Please note the comments in the code, as they explain a lot of stuff:
#!/bin/bash
# lowerupper.sh
# Prints the lowercase version of a char
lowercaseChar(){
case "$1" in
[A-Z])
n=$(printf "%d" "'$1")
n=$((n+32))
printf \\$(printf "%o" "$n")
;;
*)
printf "%s" "$1"
;;
esac
}
# Prints the lowercase version of a sequence of strings
lowercase() {
word="$@"
for((i=0;i<${#word};i++)); do
ch="${word:$i:1}"
lowercaseChar "$ch"
done
}
# Prints the uppercase version of a char
uppercaseChar(){
case "$1" in
[a-z])
n=$(printf "%d" "'$1")
n=$((n-32))
printf \\$(printf "%o" "$n")
;;
*)
printf "%s" "$1"
;;
esac
}
# Prints the uppercase version of a sequence of strings
uppercase() {
word="$@"
for((i=0;i<${#word};i++)); do
ch="${word:$i:1}"
uppercaseChar "$ch"
done
}
# The functions will not add a new line, so use echo or
# append it if you want a new line after printing
# Printing stuff directly
lowercase "I AM the Walrus!"$'\n'
uppercase "I AM the Walrus!"$'\n'
echo "----------"
# Printing a var
str="A StRing WITH mixed sTUFF!"
lowercase "$str"$'\n'
uppercase "$str"$'\n'
echo "----------"
# Not quoting the var should also work,
# since we use "$@" inside the functions
lowercase $str$'\n'
uppercase $str$'\n'
echo "----------"
# Assigning to a var
myLowerVar="$(lowercase $str)"
myUpperVar="$(uppercase $str)"
echo "myLowerVar: $myLowerVar"
echo "myUpperVar: $myUpperVar"
echo "----------"
# You can even do stuff like
if [[ 'option 2' = "$(lowercase 'OPTION 2')" ]]; then
echo "Fine! All the same!"
else
echo "Ops! Not the same!"
fi
exit 0
And the results after running this:
$ ./lowerupper.sh
i am the walrus!
I AM THE WALRUS!
----------
a string with mixed stuff!
A STRING WITH MIXED STUFF!
----------
a string with mixed stuff!
A STRING WITH MIXED STUFF!
----------
myLowerVar: a string with mixed stuff!
myUpperVar: A STRING WITH MIXED STUFF!
----------
Fine! All the same!
This should only work for ASCII characters though.
For me it is fine, since I know I will only pass ASCII chars to it. I am using this for some case-insensitive CLI options, for example.
From the bash
manpage:
${parameter^pattern} ${parameter^^pattern} ${parameter,pattern} ${parameter,,pattern} Case modification. This expansion modifies the case of alphabetic characters in parameter. The pattern is expanded to produce a pattern just as in pathname expansion. Each character in the expanded value of parameter is tested against pattern, and, if it matches the pattern, its case is converted. The pattern should not attempt to match more than one character. The ^ operator converts lowercase letters matching pattern to uppercase; the , operator converts matching uppercase letters to lowercase. The ^^ and ,, expansions convert each matched character in the expanded value; the ^ and , expansions match and convert only the first character in the expanded value. If pattern is omitted, it is treated like a ?, which matches every character. If parameter is @ or *, the case modification operation is applied to each positional parameter in turn, and the expansion is the resultant list. If parameter is an array variable subscripted with @ or *, the case modification operation is applied to each member of the array in turn, and the expansion is the resultant list.
If using v4, this is baked-in. If not, here is a simple, widely applicable solution. Other answers (and comments) on this thread were quite helpful in creating the code below.
# Like echo, but converts to lowercase
echolcase () {
tr [:upper:] [:lower:] <<< "${*}"
}
# Takes one arg by reference (var name) and makes it lowercase
lcase () {
eval "${1}"=\'$(echo ${!1//\'/"'\''"} | tr [:upper:] [:lower:] )\'
}
Notes:
Doing: a="Hi All" and then: lcase a will do the same thing as: a=$( echolcase "Hi All" )
In the lcase function, using ${!1//\'/"'\''"} instead of ${!1} allows this to work even when the string has quotes.
This is a far faster variation of JaredTS486's approach that uses native Bash capabilities (including Bash versions <4.0) to optimize his approach.
I've timed 1,000 iterations of this approach for a small string (25 characters) and a larger string (445 characters), both for lowercase and uppercase conversions. Since the test strings are predominantly lowercase, conversions to lowercase are generally faster than to uppercase.
I've compared my approach with several other answers on this page that are compatible with Bash 3.2. My approach is far more performant than most approaches documented here, and is even faster than tr
in several cases.
Here are the timing results for 1,000 iterations of 25 characters:
0.46s for my approach to lowercase; 0.96s for uppercase
1.16s for Orwellophile's approach to lowercase; 1.59s for uppercase
3.67s for tr to lowercase; 3.81s for uppercase
11.12s for ghostdog74's approach to lowercase; 31.41s for uppercase
26.25s for technosaurus' approach to lowercase; 26.21s for uppercase
25.06s for JaredTS486's approach to lowercase; 27.04s for uppercase
Timing results for 1,000 iterations of 445 characters (consisting of the poem "The Robin" by Witter Bynner):
2s for my approach to lowercase; 12s for uppercase
4s for tr to lowercase; 4s for uppercase
20s for Orwellophile's approach to lowercase; 29s for uppercase
75s for ghostdog74's approach to lowercase; 669s for uppercase. It's interesting to note how dramatic the performance difference is between a test with predominant matches vs. a test with predominant misses
467s for technosaurus' approach to lowercase; 449s for uppercase
660s for JaredTS486's approach to lowercase; 660s for uppercase. It's interesting to note that this approach generated continuous page faults (memory swapping) in Bash
Solution:
#!/bin/bash
set -e
set -u
declare LCS="abcdefghijklmnopqrstuvwxyz"
declare UCS="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
function lcase()
{
local TARGET="${1-}"
local UCHAR=''
local UOFFSET=''
while [[ "${TARGET}" =~ ([A-Z]) ]]
do
UCHAR="${BASH_REMATCH[1]}"
UOFFSET="${UCS%%${UCHAR}*}"
TARGET="${TARGET//${UCHAR}/${LCS:${#UOFFSET}:1}}"
done
echo -n "${TARGET}"
}
function ucase()
{
local TARGET="${1-}"
local LCHAR=''
local LOFFSET=''
while [[ "${TARGET}" =~ ([a-z]) ]]
do
LCHAR="${BASH_REMATCH[1]}"
LOFFSET="${LCS%%${LCHAR}*}"
TARGET="${TARGET//${LCHAR}/${UCS:${#LOFFSET}:1}}"
done
echo -n "${TARGET}"
}
The approach is simple: while the input string has any remaining uppercase letters present, find the next one, and replace all instances of that letter with its lowercase variant. Repeat until all uppercase letters are replaced.
Some performance characteristics of my solution:
Uses only shell builtin utilities, which avoids the overhead of invoking external binary utilities in a new process Avoids sub-shells, which incur performance penalties Uses shell mechanisms that are compiled and optimized for performance, such as global string replacement within variables, variable suffix trimming, and regex searching and matching. These mechanisms are far faster than iterating manually through strings Loops only the number of times required by the count of unique matching characters to be converted. For example, converting a string that has three different uppercase characters to lowercase requires only 3 loop iterations. For the preconfigured ASCII alphabet, the maximum number of loop iterations is 26 UCS and LCS can be augmented with additional characters
For Bash versions earlier than 4.0, this version should be fastest (as it doesn't fork/exec any commands):
function string.monolithic.tolower
{
local __word=$1
local __len=${#__word}
local __char
local __octal
local __decimal
local __result
for (( i=0; i<__len; i++ ))
do
__char=${__word:$i:1}
case "$__char" in
[A-Z] )
printf -v __decimal '%d' "'$__char"
printf -v __octal '%03o' $(( $__decimal ^ 0x20 ))
printf -v __char \\$__octal
;;
esac
__result+="$__char"
done
REPLY="$__result"
}
technosaurus's answer had potential too, although it did run properly for mee.
In spite of how old this question is and similar to this answer by technosaurus. I had a hard time finding a solution that was portable across most platforms (That I Use) as well as older versions of bash. I have also been frustrated with arrays, functions and use of prints, echos and temporary files to retrieve trivial variables. This works very well for me so far I thought I would share. My main testing environments are:
GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu) GNU bash, version 3.2.57(1)-release (sparc-sun-solaris2.10)
lcs="abcdefghijklmnopqrstuvwxyz"
ucs="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
input="Change Me To All Capitals"
for (( i=0; i<"${#input}"; i++ )) ; do :
for (( j=0; j<"${#lcs}"; j++ )) ; do :
if [[ "${input:$i:1}" == "${lcs:$j:1}" ]] ; then
input="${input/${input:$i:1}/${ucs:$j:1}}"
fi
done
done
Simple C-style for loop to iterate through the strings. For the line below if you have not seen anything like this before this is where I learned this. In this case the line checks if the char ${input:$i:1} (lower case) exists in input and if so replaces it with the given char ${ucs:$j:1} (upper case) and stores it back into input.
input="${input/${input:$i:1}/${ucs:$j:1}}"
To store the transformed string into a variable. Following worked for me - $SOURCE_NAME
to $TARGET_NAME
TARGET_NAME="`echo $SOURCE_NAME | tr '[:upper:]' '[:lower:]'`"
so i attempted to perform some updated benchmarking using the consensus approach for each utility, but instead of repeating a tiny set many times, I ...
fed in a 1.85 GB .txt file that's filled to the brim w/ multi-byte Unicode chars in UTF-8 encoding, via the pipe in order to equalize I/O aspect, while also enforcing LC_ALL=C for all to ensure level playing field
————————————————————————————————————————
Both bsd-sed and gnu-sed are rather mediocre, to put it very nicely. I don't even know what bsd-sed was trying to do, as their xxhash doesn't match
I don't even know what bsd-sed was trying to do, as their xxhash doesn't match
was python3 trying to do Unicode letter-casing ? (even though I already forced the locale setting LC_ALL=C )
(even though I already forced the locale setting LC_ALL=C )
tr is the most extreme gnu-tr is, by far, the fastest among all bsd-tr utterly atrocious
gnu-tr is, by far, the fastest among all
bsd-tr utterly atrocious
perl5 is faster than any awk variant I have, unless you're okay with loading the whole file at once using mawk2 in order to gain a tiny bit over perl5 : 2.935s mawk2 vs 3.081s perl5
within awk, gnu-gawk appears slowest among the 3 , mawk 1.3.4 in the middle, and mawk 1.9.9.6 fastest : more than 50% time savings over gawk . (I didn't waste my time with the useless macosx nawk)
.
out9: 1.85GiB 0:00:03 [ 568MiB/s] [ 568MiB/s] [ <=> ]
in0: 1.85GiB 0:00:03 [ 568MiB/s] [ 568MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C mawk2 '{ print tolower($_) }' FS='^$'; )
mawk 1.9.9.6 (mawk2-beta)
3.07s user 0.66s system 111% cpu 3.348 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 1.85GiB 0:00:06 [ 297MiB/s] [ 297MiB/s] [ <=> ]
in0: 1.85GiB 0:00:06 [ 297MiB/s] [ 297MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C mawk '{ print tolower($_) }' FS='^$'; )
mawk 1.3.4
6.01s user 0.83s system 107% cpu 6.368 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 23.8MiB 0:00:00 [ 238MiB/s] [ 238MiB/s] [ <=> ]
in0: 1.85GiB 0:00:07 [ 244MiB/s] [ 244MiB/s] [============>] 100%
out9: 1.85GiB 0:00:07 [ 244MiB/s] [ 244MiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C gawk -be '{ print tolower($_) }' FS='^$';
GNU Awk 5.1.1, API: 3.1 (GNU MPFR 4.1.0, GNU MP 6.2.1)
7.49s user 0.78s system 106% cpu 7.763 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 1.85GiB 0:00:03 [ 616MiB/s] [ 616MiB/s] [ <=> ]
in0: 1.85GiB 0:00:03 [ 617MiB/s] [ 617MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C perl -ne 'print lc'; )
perl5 (revision 5 version 34 subversion 0)
2.70s user 0.85s system 115% cpu 3.081 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 1.85GiB 0:00:32 [57.4MiB/s] [57.4MiB/s] [ <=> ]
in0: 1.85GiB 0:00:32 [57.4MiB/s] [57.4MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C gsed 's/.*/\L&/'; ) # GNU-sed
gsed (GNU sed) 4.8
32.57s user 0.97s system 101% cpu 32.982 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 1.86GiB 0:00:38 [49.7MiB/s] [49.7MiB/s] [ <=> ]
in0: 1.85GiB 0:00:38 [49.4MiB/s] [49.4MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C sed 's/.*/\L&/'; ) # BSD-sed
37.94s user 0.86s system 101% cpu 38.318 total
d5e2d8487df1136db7c2334a238755c0 stdin
in0: 313MiB 0:00:00 [3.06GiB/s] [3.06GiB/s] [=====>] 16% ETA 0:00:00
out9: 1.85GiB 0:00:11 [ 166MiB/s] [ 166MiB/s] [ <=>]
in0: 1.85GiB 0:00:00 [3.31GiB/s] [3.31GiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C python3 -c "print(open(0).read().lower()))
Python 3.9.12
9.04s user 2.18s system 98% cpu 11.403 total
7ddc0b5cbcfbbfac3c2b6da6731bd262 stdin
out9: 2.51MiB 0:00:00 [25.1MiB/s] [25.1MiB/s] [ <=> ]
in0: 1.85GiB 0:00:11 [ 171MiB/s] [ 171MiB/s] [============>] 100%
out9: 1.85GiB 0:00:11 [ 171MiB/s] [ 171MiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C ruby -pe '$_.downcase!'; )
ruby 2.6.8p205 (2021-07-07 revision 67951) [universal.arm64e-darwin21]
10.46s user 1.23s system 105% cpu 11.073 total
85759a34df874966d096c6529dbfb9d5 stdin
in0: 1.85GiB 0:00:01 [1.01GiB/s] [1.01GiB/s] [============>] 100%
out9: 1.85GiB 0:00:01 [1.01GiB/s] [1.01GiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C gtr '[A-Z]' '[a-z]'; ) # GNU-tr
gtr (GNU coreutils) 9.1
1.11s user 1.21s system 124% cpu 1.855 total
85759a34df874966d096c6529dbfb9d5 stdin
out9: 1.85GiB 0:01:19 [23.7MiB/s] [23.7MiB/s] [ <=> ]
in0: 1.85GiB 0:01:19 [23.7MiB/s] [23.7MiB/s] [============>] 100%
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C tr '[A-Z]' '[a-z]'; ) # BSD-tr
78.94s user 1.50s system 100% cpu 1:19.67 total
85759a34df874966d096c6529dbfb9d5 stdin
( time ( pvE0 < "${m3t}" | LC_ALL=C gdd conv=lcase ) | pvE9 ) | xxh128sum | lgp3; sleep 3;
out9: 0.00 B 0:00:01 [0.00 B/s] [0.00 B/s] [<=> ]
in0: 1.85GiB 0:00:06 [ 295MiB/s] [ 295MiB/s] [============>] 100%
out9: 1.81GiB 0:00:06 [ 392MiB/s] [ 294MiB/s] [ <=> ]
3874110+1 records in
3874110+1 records out
out9: 1.85GiB 0:00:06 [ 295MiB/s] [ 295MiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C gdd conv=lcase; ) # GNU-dd
gdd (coreutils) 9.1
1.93s user 4.35s system 97% cpu 6.413 total
85759a34df874966d096c6529dbfb9d5 stdin
% ( time ( pvE0 < "${m3t}" | LC_ALL=C dd conv=lcase ) | pvE9 ) | xxh128sum | lgp3; sleep 3;
out9: 36.9MiB 0:00:00 [ 368MiB/s] [ 368MiB/s] [ <=> ]
in0: 1.85GiB 0:00:04 [ 393MiB/s] [ 393MiB/s] [============>] 100%
out9: 1.85GiB 0:00:04 [ 393MiB/s] [ 393MiB/s] [ <=> ]
3874110+1 records in
3874110+1 records out
out9: 1.85GiB 0:00:04 [ 393MiB/s] [ 393MiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C dd conv=lcase; ) # BSD-dd
1.92s user 4.24s system 127% cpu 4.817 total
85759a34df874966d096c6529dbfb9d5 stdin
————————————————————————————————————————
mawk2
can be made artificially faster than perl5
by having the file load all at once, and doing tolower()
for all 1.85 GB
in a single function call ::
( time ( pvE0 < "${m3t}" |
LC_ALL=C mawk2 '
BEGIN { FS = RS = "^$" }
END { print tolower($(ORS = "")) }'
) | pvE9 ) | xxh128sum| lgp3
in0: 1.85GiB 0:00:00 [3.35GiB/s] [3.35GiB/s] [============>] 100%
out9: 1.85GiB 0:00:02 [ 647MiB/s] [ 647MiB/s] [ <=> ]
( pvE 0.1 in0 < "${m3t}" | LC_ALL=C mawk2 ; )
1.39s user 1.31s system 91% cpu 2.935 total
85759a34df874966d096c6529dbfb9d5 stdin
Based on Dejay Clayton excellent solution, I've generalized the uppercase/lowercase to a transpose function (independently useful), returned the result in a variable (faster/safer), and added a BASH v4+ optimization:
pkg::transpose() { # <retvar> <string> <from> <to>
local __r=$2 __m __p
while [[ ${__r} =~ ([$3]) ]]; do
__m="${BASH_REMATCH[1]}"; __p="${3%${__m}*}"
__r="${__r//${__m}/${4:${#__p}:1}}"
done
printf -v "$1" "%s" "${__r}"
}
pkg::lowercase() { # <retvar> <string>
if (( BASH_VERSINFO[0] >= 4 )); then
printf -v "$1" "%s" "${2,,}"
else
pkg::transpose "$1" "$2" "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
"abcdefghijklmnopqrstuvwxyz"
fi
}
pkg::uppercase() { # <retvar> <string>
if (( BASH_VERSINFO[0] >= 4 )); then
printf -v "$1" "%s" "${2^^}"
else
pkg::transpose "$1" "$2" "abcdefghijklmnopqrstuvwxyz" \
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
fi
}
To keep things simple I didn't add any set -e support (or any error checking really)... but otherwise it generally follows shellguide and pkg::transpose()
tries to avoid any likely variable name clashes for the printf -v
use this command to do the same , it will convert upper case strings into lowercase :
sed 's/[A-Z]/[a-z]/g' <filename>
[a-z]
!
Success story sharing
word="Hi All"
like the other examples, it returnsha
, nothi all
. It only works for the capitalized letters and skips the already-lowercased letters.tr
andawk
examples are specified in the POSIX standard.tr '[:upper:]' '[:lower:]'
will use the current locale to determine uppercase/lowercase equivalents, so it'll work with locales that use letters with diacritical marks.b="$(echo $a | tr '[A-Z]' '[a-z]')"