cut是切割文件用，簡單取列的命令

cut常見命令參數

  -b, --bytes=LIST        select only these bytes
  -c, --characters=LIST   select only these characters
  -d, --delimiter=DELIM   use DELIM instead of TAB for field delimiter
  -f, --fields=LIST       select only these fields;  also print any line
                            that contains no delimiter character, unless
                            the -s option is specified
  -n                      with -b: don‘t split multibyte characters
      --complement        complement the set of selected bytes, characters
                            or fields
  -s, --only-delimited    do not print lines not containing delimiters
      --output-delimiter=STRING  use STRING as the output delimiter
                            the default is to use the input delimiter
      --help     display this help and exit
      --version  output version information and exit

常用的命令展示

設置特定切割符，取特定的列

cut -d ‘/‘ -f3 logs.txt    設置/為切割符   -f 表示第幾列,這裏取第三列

查找特定數量的字符

[root@localhost ftl]# cat logs.txt 
/var/log/yum.log
hello world
[root@localhost ftl]# cut -c 1-5 logs.txt 

替換文件內的內容：源文件不受影響

tr ‘var‘ ‘log‘ < logs_bak.txt| head -3

Linux cut命令詳解