Subroutine/Procedure/Function that Reads from Standard Input (Pipe)

The procedure "pipe2dbg()" reads from the standard input (from a pipe), copies the input to the standard output and - if enabled - also to a debug log file.

# Enables/disables the debugging 

typeset -r C_DO_DBG="Y"

# Define the path of the debug log file

typeset -r C_DBG_FILE="/tmp/myDebugFile.log"

pipe2dbg () {

  if [[ -n "${C_DBG_FILE}" && "${C_DO_DBG}" == "Y" ]]; then

    while read line; do

      print - "${line}" | tee -a ${C_DBG_FILE}

    done

  else

    while read line; do

      print - "${line}"

    done

  fi

}

The procedure "pipe2stderr()" reads from the standard input (from a pipe), copies the input to the standard output and if one of the keywords "error|warning|sorry" are found, writes to the standard error output (see "1>&2") instead of standard output:

pipe2stderr () {

  typeset L_ERR_STR

  while read line; do

    L_ERR_STR="$(print - "${line}" | egrep -e 'error|warning|sorry')"

    if [[ -n "${L_ERR_STR}" ]]; then

      print - "E: ${L_ERR_STR}" 1>&2

    else

      print - "${line}"

    fi

  done

}

Usage examples in ksh/bash scripts.

Example 1

. . .

print - "Write this to the standard output and to the debug log file" | pipe2dbg

. . .

Example 2

Writing the output of Oracle sqlplus SQL statements to the standard output with the possibility to enable disable the debugging output to a debug log file:

. . .

sqlplus -SILENT /NOLOG <<EOSQL | pipe2dbg

  CONNECT <DbUser>/<Password>

  <SQL Statements>

EOSQL

. . .