Often you may want to use Bash to remove the first and last characters from a string.
The easiest way to do so is by using sed with the following syntax:
sed -e 's/^.//' -e 's/.$//' cities.txt
This particular example will remove the first and last character from each line in the file named cities.txt.
Here is what the various commands do:
- -e: Specifies that the string that follows should be interpreted as a sed expression
- s/^.//: Used to “substitute” the first character ( ^. ) with nothing
- s/.$//: Used to “substitute” the last character ( .$ ) with nothing
The following example shows how to use this syntax in practice.
Example: Use Bash to Remove First and Last Characters from String
Suppose that we have a file named cities.txt that contains the names of various U.S. cities.
We can use the cat command to view the contents of this file:
Suppose that we would like to remove the first and last characters from each city name in the file.
We can use the following syntax to do so:
sed -e 's/^.//' -e 's/.$//' cities.txt
The following screenshot shows how to use this syntax in practice:
Notice that the first and last character have been removed from each city name in the file.
Also note that you could use the > command to save these results to a new file:
sed -e 's/^.//' -e 's/.$//' cities.txt > cities_new.txt
This syntax would remove the first and last character from each city name in the file named cities.txt and save the results to a new file named cities_new.txt.
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Extract Text Between Two Strings
Bash: How to Replace Multiple Characters in String
Bash: How to Replace All Occurrences of String in File
