I want to put the result of the sort method into an array where each cell contains a word. I tried this code but only part of the $file is printed and its not sorted:
#!/bin/bash
for file in `ls ${1}` ; do
if [[ ! ($file = *.user) ]] ; then
continue
fi
arr=(`sort -nrk4 $file`)
echo ${arr[*]}
done
Why isnt this working? How can I do this?
Data file:
name1 01/01/1994 a 0
name2 01/01/1994 b 5
name3 01/01/1994 c 2
If I run the sort line only (sort -nrk4 $file), this is whats printed:
name2 01/01/1994 b 5
name3 01/01/1994 c 2
name1 01/01/1994 a 0
When I run the 2 lines above, this is what its printed:
name1 01/01/1994 a 0
In order for each line of the sort output to be put into its own array element, IFS needs to be set to a newline. To output the array, you need to iterate over it.
#!/bin/bash
for file in $1; do
if [[ ! $file = *.user ]]; then
continue
fi
saveIFS=$IFS
IFS=$'\n'
arr=($(sort -nrk4 "$file"))
IFS=$saveIFS
for i in "${arr[#]}"
do
echo "$i"
done
done
Alternatively, don't reset IFS, don't use a loop for output and the following command will output the elements separated by newlines since the first character of IFS is used for the output separator when * is used for the subscript in a quoted context:
echo "${arr[*]}"
Remember, quoting fixes everything.
Don't use ls in a for loop. If $1 may contain globbing, then it should be left unquoted. It not, then it should be quoted in case the directory or filename may contain whitespace characters. Ideally, the contents of $1 should be validated before they're used here.
The comparison operators have higher precedence than the negation operator so the parentheses are unnecessary.
For command substitution, $() is preferred over backticks. They're more readable and easier to use nested.
And finally, when variables are expanded, the should be quoted. Also, # should almost always be used to subscript arrays.
Related
I have a string in a Bash shell script that I want to split into an array of characters, not based on a delimiter but just one character per array index. How can I do this? Ideally it would not use any external programs. Let me rephrase that. My goal is portability, so things like sed that are likely to be on any POSIX compatible system are fine.
Try
echo "abcdefg" | fold -w1
Edit: Added a more elegant solution suggested in comments.
echo "abcdefg" | grep -o .
You can access each letter individually already without an array conversion:
$ foo="bar"
$ echo ${foo:0:1}
b
$ echo ${foo:1:1}
a
$ echo ${foo:2:1}
r
If that's not enough, you could use something like this:
$ bar=($(echo $foo|sed 's/\(.\)/\1 /g'))
$ echo ${bar[1]}
a
If you can't even use sed or something like that, you can use the first technique above combined with a while loop using the original string's length (${#foo}) to build the array.
Warning: the code below does not work if the string contains whitespace. I think Vaughn Cato's answer has a better chance at surviving with special chars.
thing=($(i=0; while [ $i -lt ${#foo} ] ; do echo ${foo:$i:1} ; i=$((i+1)) ; done))
As an alternative to iterating over 0 .. ${#string}-1 with a for/while loop, there are two other ways I can think of to do this with only bash: using =~ and using printf. (There's a third possibility using eval and a {..} sequence expression, but this lacks clarity.)
With the correct environment and NLS enabled in bash these will work with non-ASCII as hoped, removing potential sources of failure with older system tools such as sed, if that's a concern. These will work from bash-3.0 (released 2005).
Using =~ and regular expressions, converting a string to an array in a single expression:
string="wonkabars"
[[ "$string" =~ ${string//?/(.)} ]] # splits into array
printf "%s\n" "${BASH_REMATCH[#]:1}" # loop free: reuse fmtstr
declare -a arr=( "${BASH_REMATCH[#]:1}" ) # copy array for later
The way this works is to perform an expansion of string which substitutes each single character for (.), then match this generated regular expression with grouping to capture each individual character into BASH_REMATCH[]. Index 0 is set to the entire string, since that special array is read-only you cannot remove it, note the :1 when the array is expanded to skip over index 0, if needed.
Some quick testing for non-trivial strings (>64 chars) shows this method is substantially faster than one using bash string and array operations.
The above will work with strings containing newlines, =~ supports POSIX ERE where . matches anything except NUL by default, i.e. the regex is compiled without REG_NEWLINE. (The behaviour of POSIX text processing utilities is allowed to be different by default in this respect, and usually is.)
Second option, using printf:
string="wonkabars"
ii=0
while printf "%s%n" "${string:ii++:1}" xx; do
((xx)) && printf "\n" || break
done
This loop increments index ii to print one character at a time, and breaks out when there are no characters left. This would be even simpler if the bash printf returned the number of character printed (as in C) rather than an error status, instead the number of characters printed is captured in xx using %n. (This works at least back as far as bash-2.05b.)
With bash-3.1 and printf -v var you have slightly more flexibility, and can avoid falling off the end of the string should you be doing something other than printing the characters, e.g. to create an array:
declare -a arr
ii=0
while printf -v cc "%s%n" "${string:(ii++):1}" xx; do
((xx)) && arr+=("$cc") || break
done
If your string is stored in variable x, this produces an array y with the individual characters:
i=0
while [ $i -lt ${#x} ]; do y[$i]=${x:$i:1}; i=$((i+1));done
The most simple, complete and elegant solution:
$ read -a ARRAY <<< $(echo "abcdefg" | sed 's/./& /g')
and test
$ echo ${ARRAY[0]}
a
$ echo ${ARRAY[1]}
b
Explanation: read -a reads the stdin as an array and assigns it to the variable ARRAY treating spaces as delimiter for each array item.
The evaluation of echoing the string to sed just add needed spaces between each character.
We are using Here String (<<<) to feed the stdin of the read command.
I have found that the following works the best:
array=( `echo string | grep -o . ` )
(note the backticks)
then if you do: echo ${array[#]} ,
you get: s t r i n g
or: echo ${array[2]} ,
you get: r
Pure Bash solution with no loop:
#!/usr/bin/env bash
str='The quick brown fox jumps over a lazy dog.'
# Need extglob for the replacement pattern
shopt -s extglob
# Split string characters into array (skip first record)
# Character 037 is the octal representation of ASCII Record Separator
# so it can capture all other characters in the string, including spaces.
IFS= mapfile -s1 -t -d $'\37' array <<<"${str//?()/$'\37'}"
# Strip out captured trailing newline of here-string in last record
array[-1]="${array[-1]%?}"
# Debug print array
declare -p array
string=hello123
for i in $(seq 0 ${#string})
do array[$i]=${string:$i:1}
done
echo "zero element of array is [${array[0]}]"
echo "entire array is [${array[#]}]"
The zero element of array is [h]. The entire array is [h e l l o 1 2 3 ].
Yet another on :), the stated question simply says 'Split string into character array' and don't say much about the state of the receiving array, and don't say much about special chars like and control chars.
My assumption is that if I want to split a string into an array of chars I want the receiving array containing just that string and no left over from previous runs, yet preserve any special chars.
For instance the proposed solution family like
for (( i=0 ; i < ${#x} ; i++ )); do y[i]=${x:i:1}; done
Have left overs in the target array.
$ y=(1 2 3 4 5 6 7 8)
$ x=abc
$ for (( i=0 ; i < ${#x} ; i++ )); do y[i]=${x:i:1}; done
$ printf '%s ' "${y[#]}"
a b c 4 5 6 7 8
Beside writing the long line each time we want to split a problem, so why not hide all this into a function we can keep is a package source file, with a API like
s2a "Long string" ArrayName
I got this one that seems to do the job.
$ s2a()
> { [ "$2" ] && typeset -n __=$2 && unset $2;
> [ "$1" ] && __+=("${1:0:1}") && s2a "${1:1}"
> }
$ a=(1 2 3 4 5 6 7 8 9 0) ; printf '%s ' "${a[#]}"
1 2 3 4 5 6 7 8 9 0
$ s2a "Split It" a ; printf '%s ' "${a[#]}"
S p l i t I t
If the text can contain spaces:
eval a=( $(echo "this is a test" | sed "s/\(.\)/'\1' /g") )
$ echo hello | awk NF=NF FS=
h e l l o
Or
$ echo hello | awk '$0=RT' RS=[[:alnum:]]
h
e
l
l
o
I know this is a "bash" question, but please let me show you the perfect solution in zsh, a shell very popular these days:
string='this is a string'
string_array=(${(s::)string}) #Parameter expansion. And that's it!
print ${(t)string_array} -> type array
print $#string_array -> 16 items
This is an old post/thread but with a new feature of bash v5.2+ using the shell option patsub_replacement and the =~ operator for regex. More or less same with #mr.spuratic post/answer.
str='There can be only one, the Highlander.'
regexp="${str//?/(&)}"
[[ "$str" =~ $regexp ]] &&
printf '%s\n' "${BASH_REMATCH[#]:1}"
Or by just: (which includes the whole string at index 0)
declare -p BASH_REMATCH
If that is not desired, one can remove the value of the first index (index 0), with
unset -v 'BASH_REMATCH[0]'
instead of using printf or echo to print the value of the array BASH_REMATCH
One can check/see the value of the variable "$regexp" with either
declare -p regexp
Output
declare -- regexp="(T)(h)(e)(r)(e)( )(c)(a)(n)( )(b)(e)( )(o)(n)(l)(y)( )(o)(n)(e)(,)( )(t)(h)(e)( )(H)(i)(g)(h)(l)(a)(n)(d)(e)(r)(.)"
or
echo "$regexp"
Using it in a script, one might want to test if the shopt is enabled or not, although the manual says it is on/enabled by default.
Something like.
if ! shopt -q patsub_replacement; then
shopt -s patsub_replacement
fi
But yeah, check the bash version too! If you're not sure which version of bash is in use.
if ! ((BASH_VERSINFO[0] >= 5 && BASH_VERSINFO[1] >= 2)); then
printf 'No dice! bash version 5.2+ is required!\n' >&2
exit 1
fi
Space can be excluded from regexp variable, change it from
regexp="${str//?/(&)}"
To
regexp="${str//[! ]/(&)}"
and the output is:
declare -- regexp="(T)(h)(e)(r)(e) (c)(a)(n) (b)(e) (o)(n)(l)(y) (o)(n)(e) (t)(h)(e) (H)(i)(g)(h)(l)(a)(n)(d)(e)(r)(.)"
Maybe not as efficient as the other post/answer but it is still a solution/option.
If you want to store this in an array, you can do this:
string=foo
unset chars
declare -a chars
while read -N 1
do
chars[${#chars[#]}]="$REPLY"
done <<<"$string"x
unset chars[$((${#chars[#]} - 1))]
unset chars[$((${#chars[#]} - 1))]
echo "Array: ${chars[#]}"
Array: f o o
echo "Array length: ${#chars[#]}"
Array length: 3
The final x is necessary to handle the fact that a newline is appended after $string if it doesn't contain one.
If you want to use NUL-separated characters, you can try this:
echo -n "$string" | while read -N 1
do
printf %s "$REPLY"
printf '\0'
done
AWK is quite convenient:
a='123'; echo $a | awk 'BEGIN{FS="";OFS=" "} {print $1,$2,$3}'
where FS and OFS is delimiter for read-in and print-out
For those who landed here searching how to do this in fish:
We can use the builtin string command (since v2.3.0) for string manipulation.
↪ string split '' abc
a
b
c
The output is a list, so array operations will work.
↪ for c in (string split '' abc)
echo char is $c
end
char is a
char is b
char is c
Here's a more complex example iterating over the string with an index.
↪ set --local chars (string split '' abc)
for i in (seq (count $chars))
echo $i: $chars[$i]
end
1: a
2: b
3: c
zsh solution: To put the scalar string variable into arr, which will be an array:
arr=(${(ps::)string})
If you also need support for strings with newlines, you can do:
str2arr(){ local string="$1"; mapfile -d $'\0' Chars < <(for i in $(seq 0 $((${#string}-1))); do printf '%s\u0000' "${string:$i:1}"; done); printf '%s' "(${Chars[*]#Q})" ;}
string=$(printf '%b' "apa\nbepa")
declare -a MyString=$(str2arr "$string")
declare -p MyString
# prints declare -a MyString=([0]="a" [1]="p" [2]="a" [3]=$'\n' [4]="b" [5]="e" [6]="p" [7]="a")
As a response to Alexandro de Oliveira, I think the following is more elegant or at least more intuitive:
while read -r -n1 c ; do arr+=("$c") ; done <<<"hejsan"
declare -r some_string='abcdefghijklmnopqrstuvwxyz'
declare -a some_array
declare -i idx
for ((idx = 0; idx < ${#some_string}; ++idx)); do
some_array+=("${some_string:idx:1}")
done
for idx in "${!some_array[#]}"; do
echo "$((idx)): ${some_array[idx]}"
done
Pure bash, no loop.
Another solution, similar to/adapted from Léa Gris' solution, but using read -a instead of readarray/mapfile :
#!/usr/bin/env bash
str='azerty'
# Need extglob for the replacement pattern
shopt -s extglob
# Split string characters into array
# ${str//?()/$'\x1F'} replace each character "c" with "^_c".
# ^_ (Control-_, 0x1f) is Unit Separator (US), you can choose another
# character.
IFS=$'\x1F' read -ra array <<< "${str//?()/$'\x1F'}"
# now, array[0] contains an empty string and the rest of array (starting
# from index 1) contains the original string characters :
declare -p array
# Or, if you prefer to keep the array "clean", you can delete
# the first element and pack the array :
unset array[0]
array=("${array[#]}")
declare -p array
However, I prefer the shorter (and easier to understand for me), where we remove the initial 0x1f before assigning the array :
#!/usr/bin/env bash
str='azerty'
shopt -s extglob
tmp="${str//?()/$'\x1F'}" # same as code above
tmp=${tmp#$'\x1F'} # remove initial 0x1f
IFS=$'\x1F' read -ra array <<< "$tmp" # assign array
declare -p array # verification
In bash shell I have a command that prints variable name and values such as:
Hello mate this is you variables:
MY_VAR1= this is the value of the first var
MY_VAR2= subvar1=27, subvar2=hello1
Have a good day!
The value of the variables in the output can contain characters as =,commas,;,:.., but I expect to find new line at the end of each variable value.
I need to create a short script which reads the values of MY_VAR1 and MY_VAR2.
So I need to end up with 2 variables as follows:
MY_VAR1 = this is the value of the first var
MY_VAR2 = subvar1=27, subvar2=hello1
I have a basic installation of CentOS 7, and I can't install additional stuff in that machine.
How can I achieve it?
I assume that the variable names are everything from the beginning of the lines, up to the = sign (excluded) with leading and trailing blanks removed (you cannot have blanks in your variable names).
If all you want is print the output you show, you can use something like:
while read line; do
if [[ $line =~ ^[[:blank:]]*([^[:blank:]]+)[[:blank:]]*=(.*)$ ]]; then
var="${BASH_REMATCH[1]}"
val="${BASH_REMATCH[2]}"
echo "$var = $val"
fi
done < <( my_command )
The =~ operator is a pattern matching with regular expressions. The regular expression ^[[:blank:]]*([^[:blank:]]+)[[:blank:]]*=(.*)$ models an output line of your command with variable assignment. It matches even if the variable name is surrounded with blanks. Two sub-expressions (enclosed in ()) are isolated: the variable name and the value. The BASH_REMATCH array contains the patterns that matched the sub-expressions in cells 1 and 2, respectively.
If you also want to assign the variables:
while read line; do
if [[ $line =~ ^[[:blank:]]*([^[:blank:]]+)[[:blank:]]*=(.*)$ ]]; then
var="${BASH_REMATCH[1]}"
val="${BASH_REMATCH[2]}"
echo "$var = $val"
declare $var="$val"
fi
done < <( my_command )
This is the script that will run if there are any "?" characters in the command line argument of the main script. I'm using i to run through the alphabet and essentially setting each "?" to $i for each letter in the alphabet. I think that the error is occurring because a special character is showing up at the end of the character array that can't be compared to "?", but I don't know how to deal with that. I did use ShellCheck already.
EDIT: The text file that is generated by the main script includes all permutations (no repeats) of the letters provided in the command line argument with a hard return between each permutation, and I am pretty sure that the hard return character is what is generating the error. Here is an example of permute.txt
at?
a?t
ta?
t?a
?at
?ta
And here is the slightly edited script:
#reads the text file produced by another script into the array
readarray words < ./permute.txt
#runs through loop 26 times with i as a letter in the alphabet
for i in {a..z}; do
#runs through every word in the array provided by the text file
for j in "${words[#]}"; do
s=$j #sets $j to a variable to mess with
declare -a a
word=""
#splits string s into character array
while read -n 1 c; do a+=($c); done <<< "$s"
#checks array for "?", used as a blank tile and changes that character to $i
for k in "${a[#]}"; do if [ "$k" = "?" ]; then a[$k]=$i; fi; done
#puts the array back together into a string
for ((k=0; k<${#a}; k++)); do echo $word; word=$word${a[$k]}; done
valid=$(grep -w $word /usr/share/dict/words) #checks for word in dictionary
#statement that fixes bug where words with apostrophes end up in the output
if [ ${#valid} -eq ${#i} ]; then
echo "$valid"
fi
done
done
Do I understand rigth, that you want wo replace the ? in the permutations with all characters a..z and then check if they are in the dictionary?
I would try without manually array work and let sed work for you (replacement of ?).
for i in {a..z}; do
for word in $(sed "s/\?/$i/" permute.txt); do
grep -w $word /usr/share/dict/words
done
done
You could even use bash's built in replacement in variables:
for i in {a..z}; do
for word in $(< permute.txt); do
grep -w ${word/\?/$i} /usr/share/dict/words
done
done
btw: I don't understand the last if statement. Since $i is a single character and $valid is a whole line, that at least contains a (in the example) 3-character word, if [ ${#valid} -eq ${#i} ] will never be true.
Consider there is a variable line and variable word:
line = 1234 abc xyz 5678
word = 1234
The value of these variables are read from 2 different files.
I want to print the line if it contains the word. How do I do this using shell script? I tried all the suggested solutions given in previous questions. For example, the following code always passed even if the word was not in the line.
if [ "$line"==*"$word"*]; then
echo $line
fi
No need for an if statement; just use grep:
echo $line | grep "\b$word\b"
You can use if [[ "$line" == *"$word"* ]]
Also you need to use the following to assign variables
line="1234 abc xyz 5678"
word="1234"
Working example -- http://ideone.com/drLidd
Watch the white spaces!
When you set a variable to a value, don't put white spaces around the equal sign. Also use quotes when your value has spaced in it:
line="1234 abc xyz 5678" # Must have quotation marks
word=1234 # Quotation marks are optional
When you use comparisons, you must leave white space around the brackets and the comparison sign:
if [[ $line == *$word* ]]; then
echo $line
fi
Note that double square brackets. If you are doing pattern matching, you must use the double square brackets and not the single square brackets. The double square brackets mean you're doing a pattern match operation when you use == or =. If you use single square brackets:
if [ "$line" = *"$word"* ]
You're doing equality. Note that double square brackets don't need quotation marks while single brackets it is required in most situations.
echo $line | grep "$word"
would be the typical way to do this in a script, of course it does cost a new process
You can use the bash match operator =~:
[[ "$line" =~ "$word" ]] && echo "$line"
Don't forget quotes, as stated in previous answers (especially the one of #Bill).
The reason that if [ "$line"==*"$word"* ] does not work as you expect is perhaps a bit obscure. Assuming that no files exist that cause the glob to expand, then you are merely testing that the string 1234 abc xyz 5678==*1234* is non empty. Clearly, that is not an empty string, so the condition is always true. You need to put whitespace around your == operator, but that will not work because you are now testing if the string 1234 abc xyz 5678 is the same as the string to which the glob *1234* expands, so it will be true only if a file named 1234 abc xyz 5678 exists in the current working directory of the process executing the shell script. There are shell extensions that allow this sort of comparison, but grep works well, or you can use a case statement:
case "$line" in
*$word*) echo $line;;
esac
An alternative solution would be using loop:
for w in $line
do
if [ "$w" == "$word" ]; then
echo $line
break
fi
done
Code Snippet:
$a='text'
$b='text'
if [ $a -eq $b ]
then
msg='equal'
fi
I have a string containing many words with at least one space between each two. How can I split the string into individual words so I can loop through them?
The string is passed as an argument. E.g. ${2} == "cat cat file". How can I loop through it?
Also, how can I check if a string contains spaces?
I like the conversion to an array, to be able to access individual elements:
sentence="this is a story"
stringarray=($sentence)
now you can access individual elements directly (it starts with 0):
echo ${stringarray[0]}
or convert back to string in order to loop:
for i in "${stringarray[#]}"
do
:
# do whatever on $i
done
Of course looping through the string directly was answered before, but that answer had the the disadvantage to not keep track of the individual elements for later use:
for i in $sentence
do
:
# do whatever on $i
done
See also Bash Array Reference.
Did you try just passing the string variable to a for loop? Bash, for one, will split on whitespace automatically.
sentence="This is a sentence."
for word in $sentence
do
echo $word
done
This
is
a
sentence.
Probably the easiest and most secure way in BASH 3 and above is:
var="string to split"
read -ra arr <<<"$var"
(where arr is the array which takes the split parts of the string) or, if there might be newlines in the input and you want more than just the first line:
var="string to split"
read -ra arr -d '' <<<"$var"
(please note the space in -d ''; it cannot be omitted), but this might give you an unexpected newline from <<<"$var" (as this implicitly adds an LF at the end).
Example:
touch NOPE
var="* a *"
read -ra arr <<<"$var"
for a in "${arr[#]}"; do echo "[$a]"; done
Outputs the expected
[*]
[a]
[*]
as this solution (in contrast to all previous solutions here) is not prone to unexpected and often uncontrollable shell globbing.
Also this gives you the full power of IFS as you probably want:
Example:
IFS=: read -ra arr < <(grep "^$USER:" /etc/passwd)
for a in "${arr[#]}"; do echo "[$a]"; done
Outputs something like:
[tino]
[x]
[1000]
[1000]
[Valentin Hilbig]
[/home/tino]
[/bin/bash]
As you can see, spaces can be preserved this way, too:
IFS=: read -ra arr <<<' split : this '
for a in "${arr[#]}"; do echo "[$a]"; done
outputs
[ split ]
[ this ]
Please note that the handling of IFS in BASH is a subject on its own, so do your tests; some interesting topics on this:
unset IFS: Ignores runs of SPC, TAB, NL and on line starts and ends
IFS='': No field separation, just reads everything
IFS=' ': Runs of SPC (and SPC only)
Some last examples:
var=$'\n\nthis is\n\n\na test\n\n'
IFS=$'\n' read -ra arr -d '' <<<"$var"
i=0; for a in "${arr[#]}"; do let i++; echo "$i [$a]"; done
outputs
1 [this is]
2 [a test]
while
unset IFS
var=$'\n\nthis is\n\n\na test\n\n'
read -ra arr -d '' <<<"$var"
i=0; for a in "${arr[#]}"; do let i++; echo "$i [$a]"; done
outputs
1 [this]
2 [is]
3 [a]
4 [test]
BTW:
If you are not used to $'ANSI-ESCAPED-STRING' get used to it; it's a timesaver.
If you do not include -r (like in read -a arr <<<"$var") then read does backslash escapes. This is left as exercise for the reader.
For the second question:
To test for something in a string I usually stick to case, as this can check for multiple cases at once (note: case only executes the first match, if you need fallthrough use multiple case statements), and this need is quite often the case (pun intended):
case "$var" in
'') empty_var;; # variable is empty
*' '*) have_space "$var";; # have SPC
*[[:space:]]*) have_whitespace "$var";; # have whitespaces like TAB
*[^-+.,A-Za-z0-9]*) have_nonalnum "$var";; # non-alphanum-chars found
*[-+.,]*) have_punctuation "$var";; # some punctuation chars found
*) default_case "$var";; # if all above does not match
esac
So you can set the return value to check for SPC like this:
case "$var" in (*' '*) true;; (*) false;; esac
Why case? Because it usually is a bit more readable than regex sequences, and thanks to Shell metacharacters it handles 99% of all needs very well.
Just use the shells "set" built-in. For example,
set $text
After that, individual words in $text will be in $1, $2, $3, etc. For robustness, one usually does
set -- junk $text
shift
to handle the case where $text is empty or start with a dash. For example:
text="This is a test"
set -- junk $text
shift
for word; do
echo "[$word]"
done
This prints
[This]
[is]
[a]
[test]
$ echo "This is a sentence." | tr -s " " "\012"
This
is
a
sentence.
For checking for spaces, use grep:
$ echo "This is a sentence." | grep " " > /dev/null
$ echo $?
0
$ echo "Thisisasentence." | grep " " > /dev/null
$ echo $?
1
echo $WORDS | xargs -n1 echo
This outputs every word, you can process that list as you see fit afterwards.
(A) To split a sentence into its words (space separated) you can simply use the default IFS by using
array=( $string )
Example running the following snippet
#!/bin/bash
sentence="this is the \"sentence\" 'you' want to split"
words=( $sentence )
len="${#words[#]}"
echo "words counted: $len"
printf "%s\n" "${words[#]}" ## print array
will output
words counted: 8
this
is
the
"sentence"
'you'
want
to
split
As you can see you can use single or double quotes too without any problem
Notes:
-- this is basically the same of mob's answer, but in this way you store the array for any further needing. If you only need a single loop, you can use his answer, which is one line shorter :)
-- please refer to this question for alternate methods to split a string based on delimiter.
(B) To check for a character in a string you can also use a regular expression match.
Example to check for the presence of a space character you can use:
regex='\s{1,}'
if [[ "$sentence" =~ $regex ]]
then
echo "Space here!";
fi
For checking spaces just with bash:
[[ "$str" = "${str% *}" ]] && echo "no spaces" || echo "has spaces"
$ echo foo bar baz | sed 's/ /\n/g'
foo
bar
baz
For my use case, the best option was:
grep -oP '\w+' file
Basically this is a regular expression that matches contiguous non-whitespace characters. This means that any type and any amount of whitespace won't match. The -o parameter outputs each word matches on a different line.
Another take on this (using Perl):
$ echo foo bar baz | perl -nE 'say for split /\s/'
foo
bar
baz