如何使用awk删除文本文件指定列的最后一个字符？

Got it, let's tackle this with awk—it's the perfect tool for field-specific text tweaks like this.

The Command #

Here's a clean, readable awk command that does exactly what you need:

awk '{ 
    $4 = substr($4, 1, length($4)-1)
    $8 = substr($8, 1, length($8)-1)
    print 
}' your_input_file.txt

How It Works #

Let me break down each part so you know what's going on:

• substr($4, 1, length($4)-1): This grabs the 4th field ($4), pulls a substring starting at the first character (position 1) and ending at the second-to-last character (total length minus 1). We assign this modified string back to $4 to update the field.
• Same logic for $8: We apply the exact same substring trick to the 8th field to strip its final character.
• print: Spits out the entire line with the modified 4th and 8th fields intact.

Example Test with Your Sample Input #

If your input line is:

scff2 54 92 aa_bb_c4_1024_0_2 scff2 30 18 aa_bb_c4_1024_0_2 scff8 80 96 aa_bb_c4_24_0_2 scff8 14 42 aa_bb_c4_24_0_2 scff1 20 25 aa_bb_c4_98_0_1 scff4 11 25 aa_bb_c4_13_0_1 scff6 16 61 aa_bb_c4_84_0_1 scff6 15 16 aa_bb_c4_84_0_2

The command will output:

scff2 54 92 aa_bb_c4_1024_0 scff2 30 18 aa_bb_c4_1024_0 scff8 80 96 aa_bb_c4_24_0 scff8 14 42 aa_bb_c4_24_0 scff1 20 25 aa_bb_c4_98_0 scff4 11 25 aa_bb_c4_13_0 scff6 16 61 aa_bb_c4_84_0 scff6 15 16 aa_bb_c4_84_0

Bonus: Compact One-Liner #

If you prefer a tight, no-line-breaks version, you can write it like this:

awk '{ $4=substr($4,1,length($4)-1); $8=substr($8,1,length($8)-1); print }' your_input_file.txt

内容的提问来源于stack exchange，提问作者Chudar