foo bar
tom jerry
UNIX Linux
Each word and/or Linux is a different length. How do strip or remove the last character from each line using bash or ksh shell only on a Linux or Unix-like systems?
You can use any one of the following commands:
- Bash/ksh shell substitution
- cut command
- head command
- tail command
Bash/ksh shell substitution example
The syntax to remove last character from line or word is as follows:
x="foo bar" echo "${x%?}" |
Sample outputs:
foo ba
The % is bash parameter substitution operators which remove from shortest rear (end) pattern. You can use the bash while loop as follows:
#!/bin/bash while IFS= read -r line do echo "${line%?}" # or put updated line to a new file #echo "${line%?}" >> /tmp/newfile done < "/path/to/file" |
cut command example
The syntax is as follows:
## if length of STRING is 3, pass 2 as character positions echo "foo"| cut -c 1-2 ## if length of STRING is 14, pass 13 as character positions echo "nixCraft Linux" | cut -c 1-13 |
See also:
# Additional correction by James K; Editing by VG – log #
8 comment
whiile IFS= read -r line
whiile -> while
Did you ever heard of “wc -l”? Or “head”/”tail” commands?
Although a bit rude, the previous comment has a point: You can use head and tail to strip off characters. If you want it to be the first X or last X, you can use -/+, like so:
“foo!”
foo!”
“foo!
foo!
This is particularly useful with tree -Q (it doesn’t escape properly otherwise).
Excellent, Keilaron !
Just noticed a typo in your post (transposed cut paste):
echo '"foo!"' | head -c -2
“foo!echo '"foo!"' | tail -c +2
foo!”echo ‘”foo!”‘ | head -c -2
head: illegal byte count — -2
Odd, I just updated and it still works for me.
What do you get from head –version (which distro/OS, too)? I get head (GNU coreutils) 8.21 Packaged by Gentoo (8.21 (p1.0))…
Mostly head/tail command on *BSD/OSX and older Unix-like oses will not accept GNU/{head|tail} syntax.
Oh, good point. I even have an old Mac here I could have tested on, but I didn’t think of it. I was just thinking of Linux at the time.. and yeah, the GNU/Linux tools tend to have little quirks and additions.