Delete the last character of a string using string manipulation in shell script

With bash 4.2 and above, you can do:

${var::-1}

Example:

$ a=123
$ echo "${a::-1}"
12

Notice that for older bash ( for example, bash 3.2.5 on OS X), you should leave spaces between and after colons:

${var: : -1}

In a POSIX shell, the syntax ${t:-2} means something different - it expands to the value of t if t is set and non null, and otherwise to the value 2. To trim a single character by parameter expansion, the syntax you probably want is ${t%?}

Note that in ksh93, bash or zsh, ${t:(-2)} or ${t: -2} (note the space) are legal as a substring expansion but are probably not what you want, since they return the substring starting at a position 2 characters in from the end (i.e. it removes the first character i of the string ijk).

See the Shell Parameter Expansion section of the Bash Reference Manual for more info:

• Bash Reference Manual – Shell Parameter Expansion

Using sed it should be as fast as

sed 's/.$//'

Your single echo is then echo ljk | sed 's/.$//'.
Using this, the 1-line string could be any size.