I am reading a character from keyboard and converting it to uppercase and then displaying the character again.
But the following code produces an error:
read a;
a=echo $a | tr 'a-z' 'A-Z'
echo $a
I also tried this:
read option;
eval $(awk -v option=$option '{print "a="toupper(option);}')
echo $a
If you want to store the result of a back in a, then you can do use command substitution:
read a;
a=$(echo $a | tr 'a-z' 'A-Z')
echo $a
This can be done natively in Bash as follows:
read a;
a="${a^^}"
echo "$a"
There is no need to invoke other commands like tr, because Bash can do this itself.
See also: Bash parameter expansion.
AWK is the right way to convert upper/lower case with full Unicode Support ;-)
echo "öäüßè" | awk 'BEGIN { getline; print toupper($0) }'
Use command substitution:
a=`echo $a | tr 'a-z' 'A-Z'`
Note the ticks ` around echo and tr.
using a bash script
printf "Type your Message Here: " read message
echo Upper Case: $message | tr [:lower:] [:upper:];
echo Lower Case: $message | tr [:upper:] [:lower:]
awk is the wrong way to go here, but here's one way it could be done:
a=$(awk 'BEGIN { getline; print toupper($0) }')
echo $a
Could not get
a=`echo $a | tr 'a-z' 'A-Z'`
to work, but
a=`echo $a | tr '[a-z]' '[A-Z]'`
did (note additional regex [] brackets.
Within a /usr/bin/sh script this worked as in
...
while getopts ":l:c:" option; do
case "$option"
in
l) L_OPT=`echo ${OPTARG}| tr '[a-z]' '[A-Z]'`
;;
c) C_OPT=`echo ${OPTARG} | tr '[a-z]' [A-Z]'`
;;
\?)
echo $USAGE
exit 1
;;
esac
done
...
Related
I had problem with cut variables from string in " quotes. I have some scripts to write for my sys classes, I had a problem with a script in which I had to read input from the user in the form of (a="var1", b="var2")
I tried the code below
#!/bin/bash
read input
a=$($input | cut -d '"' -f3)
echo $a
it returns me a error "not found a command" on line 3 I tried to double brackets like
a=$(($input | cut -d '"' -f3)
but it's still wrong.
In a comment the OP gave a working answer (should post it as an answer):
#!/bin/bash
read input
a=$(echo $input | cut -d '"' -f2)
b=$(echo $input | cut -d '"' -f4)
echo sum: $(( a + b))
echo difference: $(( a - b))
This will work for user input that is exactly like a="8", b="5".
Never trust input.
You might want to add the check
if [[ ${input} =~ ^[a-z]+=\"[0-9]+\",\ [a-z]+=\"[0-9]+\"$ ]]; then
echo "Use your code"
else
echo "Incorrect input"
fi
And when you add a check, you might want to execute the input (after replacing the comma with a semicolon).
input='testa="8", testb="5"'
if [[ ${input} =~ ^[a-z]+=\"[0-9]+\",\ [a-z]+=\"[0-9]+\"$ ]];
then
eval $(tr "," ";" <<< ${input})
set | grep -E "^test[ab]="
else
echo no
fi
EDIT:
#PesaThe commented correctly about BASH_REMATCH:
When you use bash and a test on the input you can use
if [[ ${input} =~ ^[a-z]+=\"([0-9]+)\",\ [a-z]+=\"([0-9])+\"$ ]];
then
a="${BASH_REMATCH[1]}"
b="${BASH_REMATCH[2]}"
fi
To extract the digit 1 from a string "var1" you would use a Bash substring replacement most likely:
$ s="var1"
$ echo "${s//[^0-9]/}"
1
Or,
$ a="${s//[^0-9]/}"
$ echo "$a"
1
This works by replacing any non digits in a string with nothing. Which works in your example with a single number field in the string but may not be what you need if you have multiple number fields:
$ s2="1 and a 2 and 3"
$ echo "${s2//[^0-9]/}"
123
In this case, you would use sed or grep awk or a Bash regex to capture the individual number fields and keep them distinct:
$ echo "$s2" | grep -o -E '[[:digit:]]+'
1
2
3
I have this shell script variable, var. It keeps 3 entries separated by new line. From this variable var, I want to extract 2, and 0.078688. Just these two numbers.
var="USER_ID=2
# 0.078688
Suhas"
These are the code I tried:
echo "$var" | grep -o -P '(?<=\=).*(?=\n)' # For extracting 2
echo "$var" | awk -v FS="(# |\n)" '{print $2}' # For extracting 0.078688
None of the above working. What is the problem here? How to fix this ?
Just use tr alone for retaining the numerical digits, the dot (.) and the white-space and remove everything else.
tr -cd '0-9. ' <<<"$var"
2 0.078688
From the man page, of tr for usage of -c, -d flags,
tr [OPTION]... SET1 [SET2]
-c, -C, --complement
use the complement of SET1
-d, --delete
delete characters in SET1, do not translate
To store it in variables,
IFS=' ' read -r var1 var2 < <(tr -cd '0-9. ' <<<"$var")
printf "%s\n" "$var1"
2
printf "%s\n" "$var2"
2
0.078688
Or in an array as
IFS=' ' read -ra numArray < <(tr -cd '0-9. ' <<<"$var")
printf "%s\n" "${numArray[#]}"
2
0.078688
Note:- The -cd flags in tr are POSIX compliant and will work on any systems that has tr installed.
echo "$var" |grep -oP 'USER_ID=\K.*'
2
echo "$var" |grep -oP '# \K.*'
0.078688
Your solution is near to perfect, you need to chance \n to $ which represent end of line.
echo "$var" |awk -F'# ' '/#/{print $2}'
0.078688
echo "$var" |awk -F'=' '/USER_ID/{print $2}'
2
You can do it with pure bash using a regex:
#!/bin/bash
var="USER_ID=2
# 0.078688
Suhas"
[[ ${var} =~ =([0-9]+).*#[[:space:]]([0-9\.]+) ]] && result1="${BASH_REMATCH[1]}" && result2="${BASH_REMATCH[2]}"
echo "${result1}"
echo "${result2}"
With awk:
First value:
echo "$var" | grep 'USER_ID' | awk -F "=" '{print $2}'
Second value:
echo "$var" | grep '#' | awk '{print $2}'
Assuming this is the format of data as your sample
# For extracting 2
echo "$var" | sed -e '/.*=/!d' -e 's///'
echo "$var" | awk -F '=' 'NR==1{ print $2}'
# For extracting 0.078688
echo "$var" | sed -e '/.*#[[:blank:]]*/!d' -e 's///'
echo "$var" | awk -F '#' 'NR==2{ print $2}'
I have entries of the form: cat:rat and I would like to assign them to separate variables in bash. I am currently able to do this via:
A=$(echo $PAIR | tr ':' '\n' | head -n1)
B=$(echo $PAIR | tr ':' '\n' | tail -n1)
after which $A and $B are, respectively, cat and rat. echo, the two pipes and all feels a bit like overkill am I missing a much simpler way of doing this?
Using the read command
entry=cat:rat
IFS=: read A B <<< "$entry"
echo $A # => cat
echo $B # => rat
Yes using bash parameter substitution
PAIR='cat:rat'
A=${PAIR/:*/}
B=${PAIR/*:/}
echo $A
cat
echo $B
rat
Alternately, if you are willing to use an array in place of individual variables:
IFS=: read -r -a ARR <<<"${PAIR}"
echo ${ARR[0]}
cat
echo ${ARR[1]}
rat
EDIT: Refer glenn jackman's answer for the most elegant read-based solution
animal="cat:rat"
A=echo ${animal} | cut -d ":" -f1
B=echo ${animal} | cut -d ":" -f2
might not be the best solution. Just giving you a possible solution
I started with this script called wd:
cat "$#" | tr -cs '[:alpha:]' '\n' | tr '[:upper:]' '[:lower:]'
| sort | uniq -c | sort -n | awk '{print $2 " " $1}' | sort
That takes any number of files as input and prints a distribution of the words in the file like this:
wd file1 file2
blue 2
cat 3
the 5
yes 1
Now I'm trying to add 2 options to it: s and t. s causes the script to take an input file called stopwords, and deletes those words from the input file before making the distribution. t takes a number n as an argument and only outputs the top n words. Default is all words.
So, so far I have this script. Currently, my problem is when I try to use a -t 10 option for example, it tells me it cannot find the file 10, but it should be a number anyway, not a file. And, when I try to use the -s option, it simply does nothing, but does not output any error. I know this question isn't very specific, but I would appreciate any ideas on what's wrong.
#!/bin/bash
stopwords=FALSE
stopfile=""
topwords=0
while getopts s:t: option
do
case "$option"
in
s) stopwords=TRUE
stopfile="$OPTARG";;
t) topwords=$OPTARG;;
\?) echo "Usage: wd [-s stopfile] [-t n] inputfile"
echo "-s takes words in stopfile and removes them from inputfile"
echo "-t means to output only top n words"
exit 1;;
esac
done
if [ "stopwords" = FALSE ]
then
cat "$#" | tr -cs '[:alpha:]' '\n' | tr '[:upper:]' '[:lower:]'
| sort | uniq -c | sort -nr | head -n $topwords | awk '{print $2 " " $1}' | sort
else
cat "$#" | grep -v -f "$stopfile" | tr -cs '[:alpha:]' '\n' | tr '[:upper:]' '[:lower:]'
| uniq -c | sort -nr | head -n $topwords | awk '{print $2 " " $1}' | sort
fi
Usually after the while getopts loop you need to shift $((OPTIND - 1)). Following is an example I wrote before for both ksh and bash:
PROGNAME=$0
function _echo
{
printf '%s\n' "$*"
}
function usage
{
cat << END
usage: $PROGNAME [-a] [-b arg] [-h] file...
END
exit $1
}
function parseargs
{
typeset opt v
[[ $# = 0 ]] && usage 1
while getopts ":ab:h" opt "$#"; do
case $opt in
a) _echo -$opt ;;
b) _echo -$opt $OPTARG ;;
h) usage ;;
:) _echo "! option -$OPTARG wants an argument" ;;
'?') _echo "! unkown option -$OPTARG" ;;
esac
done
shift $((OPTIND - 1))
for v in "$#"; do
_echo "$v"
done
}
parseargs "$#"
I want to uppercase just the first character in my string with bash.
foo="bar";
//uppercase first character
echo $foo;
should print "Bar";
One way with bash (version 4+):
foo=bar
echo "${foo^}"
prints:
Bar
foo="$(tr '[:lower:]' '[:upper:]' <<< ${foo:0:1})${foo:1}"
One way with sed:
echo "$(echo "$foo" | sed 's/.*/\u&/')"
Prints:
Bar
$ foo="bar";
$ foo=`echo ${foo:0:1} | tr '[a-z]' '[A-Z]'`${foo:1}
$ echo $foo
Bar
To capitalize first word only:
foo='one two three'
foo="${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+)
Using awk only
foo="uNcapItalizedstrIng"
echo $foo | awk '{print toupper(substr($0,0,1))tolower(substr($0,2))}'
Here is the "native" text tools way:
#!/bin/bash
string="abcd"
first=`echo $string|cut -c1|tr [a-z] [A-Z]`
second=`echo $string|cut -c2-`
echo $first$second
just for fun here you are :
foo="bar";
echo $foo | awk '{$1=toupper(substr($1,0,1))substr($1,2)}1'
# or
echo ${foo^}
# or
echo $foo | head -c 1 | tr [a-z] [A-Z]; echo $foo | tail -c +2
# or
echo ${foo:1} | sed -e 's/^./\B&/'
It can be done in pure bash with bash-3.2 as well:
# First, get the first character.
fl=${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}"
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
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
Alternative and clean solution for both Linux and OSX, it can also be used with bash variables
python -c "print(\"abc\".capitalize())"
returns Abc
This is POSIX sh-compatible as far as I know.
upper_first.sh:
#!/bin/sh
printf "$1" | cut -c1 -z | tr -d '\0' | tr [:lower:] [:upper:]
printf "$1" | cut -c2-
cut -c1 -z ends the first string with \0 instead of \n. It gets removed with tr -d '\0'. It also works to omit the -z and use tr -d '\n' instead, but this breaks if the first character of the string is a newline.
Usage:
$ upper_first.sh foo
Foo
$
In a function:
#!/bin/sh
function upper_first ()
{
printf "$1" | cut -c1 -z | tr -d '\0' | tr [:lower:] [:upper:]
printf "$1" | cut -c2-
}
old="foo"
new="$(upper_first "$old")"
echo "$new"
Posix compliant and with less sub-processes:
v="foo[Bar]"
printf "%s" "${v%"${v#?}"}" | tr '[:lower:]' '[:upper:]' && printf "%s" "${v#?}"
==> Foo[Bar]
first-letter-to-lower () {
str=""
space=" "
for i in $#
do
if [ -z $(echo $i | grep "the\|of\|with" ) ]
then
str=$str"$(echo ${i:0:1} | tr '[A-Z]' '[a-z]')${i:1}$space"
else
str=$str${i}$space
fi
done
echo $str
}
first-letter-to-upper-xc () {
v-first-letter-to-upper | xclip -selection clipboard
}
first-letter-to-upper () {
str=""
space=" "
for i in $#
do
if [ -z $(echo $i | grep "the\|of\|with" ) ]
then
str=$str"$(echo ${i:0:1} | tr '[a-z]' '[A-Z]')${i:1}$space"
else
str=$str${i}$space
fi
done
echo $str
}
first-letter-to-lower-xc(){
v-first-letter-to-lower | xclip -selection clipboard
}
Not exactly what asked but quite helpful
declare -u foo #When the variable is assigned a value, all lower-case characters are converted to upper-case.
foo=bar
echo $foo
BAR
And the opposite
declare -l foo #When the variable is assigned a value, all upper-case characters are converted to lower-case.
foo=BAR
echo $foo
bar
What if the first character is not a letter (but a tab, a space, and a escaped double quote)? We'd better test it until we find a letter! So:
S=' \"ó foo bar\"'
N=0
until [[ ${S:$N:1} =~ [[:alpha:]] ]]; do N=$[$N+1]; done
#F=`echo ${S:$N:1} | tr [:lower:] [:upper:]`
#F=`echo ${S:$N:1} | sed -E -e 's/./\u&/'` #other option
F=`echo ${S:$N:1}
F=`echo ${F} #pure Bash solution to "upper"
echo "$F"${S:(($N+1))} #without garbage
echo '='${S:0:(($N))}"$F"${S:(($N+1))}'=' #garbage preserved
Foo bar
= \"Foo bar=