Bash remove first and last characters from a string

Here's a solution that is independent of the length of the string (bash):

string="|abcdefg|" echo "${string:1:${#string}-2}" 

Going off a few posts listed here it seems the simplest way to do it is:

string="|abcdefg|" echo ${string:1:-1} 

edit: works on ubuntu with bash 4.2; does not work on centOS with bash 4.1

Another way is to use head & tail commands:

$ echo -n "|abcdefg|" | tail -c +2 | head -c -2 abcdefg 

You can also use sed to remove the | not just referencing the symbol itself but using positional references as in:

$ echo "|abcdefg|" | sed 's:^.\(.*\).$:\1:' abcdefg 

Where ':' are the delimiters (you can replace them with / or any character not in the query, any sign following the s will do it) Here ^ (caret) means at the beginning of the input string and $ (dollar) means at the end. The . (point) that it's after the caret and the one that it's before the dollar sign represents a single character. So in other words we are deleting the first and last characters. Take in mind this will delete any characters even if | it's not present in the string.

EX:

$ echo "abcdefg" | sed 's:^.\(.*\).$:\1:' bcdef 

And another one:

string="|abcdefg|" echo "${string//|/}" 

shell function

A bit more verbose approach, but works on any sort of first and last character, doesn't have to be the same. Basic idea is that we are taking a variable, reading it character by character, and appending only those we want to a new variable

Here's that whole idea formatted into a nice function

crop_string_ends() { STR="$1" NEWSTR="" COUNT=0 while read -n 1 CHAR do COUNT=$(($COUNT+1)) if [ $COUNT -eq 1 ] || [ $COUNT -eq ${#STR} ] then continue fi NEWSTR="$NEWSTR"$CHAR done <<<"$STR" echo $NEWSTR } 

And here is that same function in action:

$> crop_string_ends "|abcdefg|" abcdefg $> crop_string_ends "HelloWorld" elloWorl 

Python

>>> mystring="|abcdefg|" >>> print(mystring[1:-1]) abcdefg 

or on command line:

$ python -c 'import sys;print sys.stdin.read()[1:-2]' <<< "|abcdefg|" abcdefg 

AWK

$ echo "|abcdefg|" | awk '{print substr($0,2,length($0)-2)}' abcdefg 

Ruby

$ ruby -ne 'print $_.split("|")[1]' <<< "|abcdefg|" abcdefg 

Small and universal solution:

expr "|abcdef|" : '.\(.*\).' 

Special in this case and allowing that the '|' character may be there or not:

expr "|abcdef" : '|*\([^|]*\)|*' 

$ string="|abcdefg|" $ string="${string#?}" && string="${string%%?}" $ echo "$string" abcdefg 

From http://tldp.org/LDP/abs/html/parameter-substitution.html

${var#Pattern}
Remove from $var the shortest part of $Pattern that matches the front end of $var.
${var%%Pattern}
Remove from $var the longest part of $Pattern that matches the back end of $var.

You can use this:

echo "|abcdefg|" | tr -d "|" 

With this line of code, you remove all |->(pipe) in the string.