curs_insstr - Linux


curs_insstr is a versatile command-line tool designed to efficiently insert or overwrite strings within arbitrary files or shell variables. It offers various options to manipulate text data with precision and control.


curs_insstr [-o <offset>] [-l <length>] [-i <input>] [-n <count>] <string|variable> <filename>


  • -o : Specify the offset (in characters) from the beginning of the file to start the insertion. Defaults to 0 (start from the beginning).
  • -l : Set the length (in characters) to overwrite or insert from the offset. Defaults to the length of the input string.
  • -i : Take the input string to insert or overwrite from standard input (stdin). Can be used to concatenate multiple commands.
  • -n : Insert the specified string or read from stdin multiple times. Defaults to 1 (single insertion).


Insert a string at byte 10 in a file:

curs_insstr -o 10 "The quick brown fox" example.txt

Overwrite 7 characters starting from byte 0:

curs_insstr -l 7 "Hello" example.txt

Read input from stdin and insert 10 times:

echo "Welcome to Linux!" | curs_insstr -n 10 my_welcome.txt

Modify a shell variable:

export SOME_VAR="1234"
curs_insstr -o 2 -l 2 "56" $SOME_VAR
echo $SOME_VAR

Common Issues

  • File permissions: Ensure you have adequate permissions to write to the target file.
  • Incorrect offset: Using an invalid offset can lead to unexpected results or errors.
  • Invalid input: Providing non-UTF-8 encoded input strings may cause garbled output.


Command chaining: curs_insstr can be combined with other commands to automate complex tasks.

find . -type f -name "*.txt" | xargs -n1 curs_insstr -s 0 "Copyright 2023"

Input redirection: Use stdin to accept input strings from other commands or processes.

grep "error" logs.txt | curs_insstr -o 100 -l 7 "**ERROR**" logs.txt

Related Commands

  • sed: A powerful editor for text manipulation, providing a wider range of options.
  • awk: A pattern scanning and processing language, offering extensive control over text operations.