Question

我正在编写一个bash脚本，用于修改一个如下所示的文件：

--- usr1 --- data data data data data data data data data data data data --- usr2 --- data data data data data data data data --- usr3 --- data data data data --- endline ---

One question is: How to add next user line --- usrn --- after last user data lines? Second one is: How to delete specific user data lines (data lines and --- userx ---) i.e. I would like to delete usr2 with all his data set.

It must work on bash 2.05 :) and I think it will use awk or sed, but I m not sure.
A little edit here: In fact usernames are not numbered. We don t know what users will come up with. We only know that the name will be inside --- pattern

Answer 1

给定变量中的用户名：

username="kasper"

删除用户分区：

sed "/$username/{:a;N;/
--- [^[:blank:]]* ---$/{s/.*
//;b};ba}" inputfile

或者对于sed的某些版本（编辑）：

sed -e "/$username/{" -e  :a  -e  N  -e  /
--- [^[:blank:]]* ---$/{s/.*
//  -e  b  -e  }  -e  ba  -e  }  inputfile

编辑：一种可能的变体，以适应前导和尾随空格：

sed -e "/$username/{" -e  :a  -e  N  -e  /
[[:blank:]]*---[[:blank:]]*[^[:blank:]]*[[:blank:]]*---[[:blank:]]*$/{s/.*
//  -e  b  -e  }  -e  ba  -e  }  inputfile

添加下一个用户部分：

sed "s/--- end/--- $username ---
data data data data
data data data data
&/"

或

sed "/--- end/i--- $username ---
datadata data data
data data data data
"

If your version of sed supp或ts in-place changes, you can do:

sed -i ...

Otherwise, you ll have to use a temp或ary file:

sed ... inputfile > tmpfile && mv tmpfile inputfile

It s best to use a utility like mktemp 或 tempfile to create a temp或ary file and use the name provided.

Answer 2

第二部分的awk解决方案：

awk -v del="usr2"  match($0,/^--- (.*) ---$/,a) {p = (a[1] != del)} p

如果头与要删除的用户匹配，则会关闭p标志，否则会打印每一行。

Answer 3

Plain shell can handle this

更新了答案，包括第二个要求。。。

#!/bin/sh

NEWUSER= John Doe 
NEWUSERDATA= how now brown cow 
REMOVEUSER= usr2 

state=COPY
while read x; do
  case "$state/$x" in
    *"/--- endline ---")
      echo --- $NEWUSER ---
      echo "$NEWUSERDATA"
      state=COPY
      ;;
    COPY/*)
      if [ "$x" == "--- $REMOVEUSER ---" ]; then
        state=REMOVE
      fi
      ;;
    REMOVE/---*)
      state=COPY
      ;;
  esac
  if [ $state != REMOVE ]; then
    echo "$x"
  fi
done

用法类似于：shnewuser.sh<；usertable.txt>；newusertable.txt

顺便说一下，还有一种编写shell脚本的替代风格，我可以称之为“gnu-configure”格式。在“替代风格”中，主循环为：

while read x; do
  case "$state/$x" in
    *"/--- endline ---")
      echo --- $NEWUSER ---
      echo "$NEWUSERDATA"
      state=COPY;;
    COPY/*)
      [ "$x" == "--- $REMOVEUSER ---" ] && state=REMOVE;;
    REMOVE/---*)
      state=COPY;;
  esac
  [ $state != REMOVE ] && echo "$x"
done

Plain shell can handle this

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