tcl在文件中的某一行插入字符串

set fileHandle [open "filename.txt" r]
set fileContent [read $fileHandle]
close $fileHandle

set lineNumber 3
set insertionString "This is the new line to be inserted"

# 将文件内容按行分割成列表
set lines [split $fileContent "\n"]

# 在指定行号后插入字符串
set lines [linsert $lines $lineNumber $insertionString]

# 将列表重新合并为字符串，并在每行之间添加换行符
set updatedContent [join $lines "\n"]

set fileHandle [open "filename.txt" w]
puts $fileHandle $updatedContent
close $fileHandle