替换UNIX文件中第一行上的字符串

我想替换第一行中存在的字符串,尽管它也存在于文件的其余行中.我怎么能通过 shell脚本来做到这一点？有人可以帮我这个.我的代码如下.我从文件中提取第一行,之后我不知道如何进行替换.任何帮助,将不胜感激.谢谢.

伙计们 – 我想替换$line中的字符串,并将新行写入同一位置的同一文件中.

码：

while read line
do
        if [[ $v_counter == 0 ]] then
                echo "$line"

                v_counter=$(($v_counter + 1));
        fi
done < "$v_Full_File_Nm"

样本数据：

输入

BUXT_CMPID|MEDICAL_RECORD_NUM|FACILITY_ID|PATIENT_LAST_NAME|PATIENT_FIRST_NAME|HOME_ADDRESS_LINE_1|HOME_ADDRESS_LINE_2|HOME_CITY|HOME_STATE|HOME_ZIP|MOSAIC_CODE|MOSAIC_DESC|DRIVE_TIME| buxt_pt_apnd_20140624_head_5records.txt
100106086|5000120878|7141|HARRIS|NEDRA|6246 PARALLEL PKWY||KANSAS CITY|KS|66102|S71|Tough Times|2|buxt_pt_apnd_20140624_head_5records.txt

产量

BUXT_CMPID|MEDICAL_RECORD_NUM|FACILITY_ID|PATIENT_LAST_NAME|PATIENT_FIRST_NAME|HOME_ADDRESS_LINE_1|HOME_ADDRESS_LINE_2|HOME_CITY|HOME_STATE|HOME_ZIP|MOSAIC_CODE|MOSAIC_DESC|DRIVE_TIME| SRC_FILE_NM
100106086|5000120878|7141|HARRIS|NEDRA|6246 PARALLEL PKWY||KANSAS CITY|KS|66102|S71|Tough Times|2|buxt_pt_apnd_20140624_head_5records.txt

从上面的示例数据我需要用SRC_FILE_NAME字符串替换buxt_pt_apnd_20140624_head_5records.txt.

sed -e '1s/fred/frog/' yourfile

sed -e "1s/$varA/$varB/" yourfile