Edit a file based on user's input using bash script

Question

I have the following file.dev

        1 DEVICES {
        2            GLOBAL-CONFIG {
        3               framerate = "20000";
        4               subframes = "0";
        5               max_consec_timeouts = "10";
        6               max_total_timeouts = "1000";
        7               schedmode = "Standard";
        8               clustermode = "Standard";
        9           }
        10           IO-DEVICES {
        11            }
        12           COMPUTING-DEVICES {
        13                RT_WORKSTATION FDT-C-XM-0120 = {
        14                    hostname = "FDT-C-XM-0120";
        15                    ipaddress = "fdt-c-XM-0120.fdtel.exter";
        16                    DISPLAYS {
        17                        main = "FDT-C-XM-0120:0.0";
        18                    }
        19                    SCHEDPARAM {
        20                        active = "0";
        21                        framerate = "20000";
        22                        subframes = "0";
        23                        max_consec_timeouts = "10";
        24                        max_total_timeouts = "1000";
        25                    }
        26                }
        27              
        28              RT_HOST fdt-c-agx-0008 = { 
        29                    hostname = "fdt-c-agx-0008";
        30                    ipaddress = "fdt-c-agx-0008";
        31                    SCHEDPARAM {
        32                        active = "0";
        33                        framerate = "20000";
        34                        subframes = "0";
        35                        max_consec_timeouts = "10";
        36                        max_total_timeouts = "1000";
        37                    }
        38                }
        39              
        40    #             RT_HOST fdt-c-agx-0003 = { 
        41    #                    hostname = "fdt-c-agx-0003";
        42    #                   ipaddress = "fdt-c-agx-0003.fdtel.exter";
        43    #                    SCHEDPARAM {
        44    #                        active = "0";
        45    #                        framerate = "20000";
        46    #                        subframes = "0";
        47    #                        max_consec_timeouts = "10";
        48    #                        max_total_timeouts = "1000";
        49    #                    }
        50    #                }
        51            }
        52        }

In this file the text parts part 1 (from line 28 till 38) and part 2 (from line 40 till 50) are parts which the user switch between. As we can see part 2 is commented out and part one is active.

So i'm trying to automate that using bash script in such a way that the user only enters the part number he wants and the other is commented out. This way the use must not comment out each line.

# example
if [ "$userEntry" = "part2"]
then
deactivate part one by typing adding from line 28 till 38 and activate part 2 by removing the #

and the output would look like

        1 DEVICES {
        2            GLOBAL-CONFIG {
        3               framerate = "20000";
        4               subframes = "0";
        5               max_consec_timeouts = "10";
        6               max_total_timeouts = "1000";
        7               schedmode = "Standard";
        8               clustermode = "Standard";
        9           }
        10           IO-DEVICES {
        11            }
        12           COMPUTING-DEVICES {
        13                RT_WORKSTATION FDT-C-XM-0120 = {
        14                    hostname = "FDT-C-XM-0120";
        15                    ipaddress = "fdt-c-XM-0120.fdtel.exter";
        16                    DISPLAYS {
        17                        main = "FDT-C-XM-0120:0.0";
        18                    }
        19                    SCHEDPARAM {
        20                        active = "0";
        21                        framerate = "20000";
        22                        subframes = "0";
        23                        max_consec_timeouts = "10";
        24                        max_total_timeouts = "1000";
        25                    }
        26                }
        27              
        28  #           RT_HOST fdt-c-agx-0008 = { 
        29  #                  hostname = "fdt-c-agx-0008";
        30  #                  ipaddress = "fdt-c-agx-0008";
        31  #                  SCHEDPARAM {
        32  #                      active = "0";
        33  #                      framerate = "20000";
        34  #                      subframes = "0";
        35  #                      max_consec_timeouts = "10";
        36  #                      max_total_timeouts = "1000";
        37  #                  }
        38  #              }
        39              
        40                  RT_HOST fdt-c-agx-0003 = { 
        41                        hostname = "fdt-c-agx-0003";
        42                       ipaddress = "fdt-c-agx-0003.fdtel.exter";
        43                        SCHEDPARAM {
        44                            active = "0";
        45                            framerate = "20000";
        46                            subframes = "0";
        47                            max_consec_timeouts = "10";
        48                            max_total_timeouts = "1000";
        49                        }
        50                    }
        51            }
        52        }

Note that the lines order in the file.dev do not change.

I hope i could make my question clear and thanks in advance

There is just one thing, how do the user know if either part1 or part2 is enabled? — Jetchisel
– Jetchisel, Commented May 2, 2021 at 19:07
Cross-site duplicate: unix.stackexchange.com/questions/128593/…. — Tsyvarev
– Tsyvarev, Commented May 8, 2021 at 18:52

Jetchisel · Accepted Answer · 2021-05-02 20:39:58Z

2

With ed if it is available/acceptable.

#!/usr/bin/env bash

if [[ "$userEntry" == "part2" ]]; then
  printf '%s\n' '40,50s/^[[:blank:]]*#//' '28,38s/^/#/' ,p Q |
  ed -s file.txt
fi

Will just print the new output to stdout but the file will not be change/edited. Change Q to w if in-place editing is needed. Remove the ,p to silence the output.

With sed

sed '40,50s/^[[:blank:]]*#//;28,38s/^/#/' file.txt

Note that different sed version has different syntax when using the -i flag if in-place editing is needed.

As per the OP's explanation.

#!/usr/bin/env bash

part1=28
part2=40

if [[ "$userEntry" == "part2" ]]; then
  if [[ $(grep -nm1 \# file.txt | cut -d':' -f1) == "$part2" ]]; then
     sed '40,50s/^[[:blank:]]*#*//;28,38s/^/#/' file.txt
  else
     sed '28,38s/^/#/' file.txt
  fi
elif [[ "$userEntry" == "part1" ]]; then
  if [[ $(grep -nm1 \# file.txt | cut -d':' -f1) == "$part1" ]]; then
     sed '28,38s/^[[:blank:]]*#*//;40,50s/^/#/' file.txt
  else
     sed '40,50s/^/#/' file.txt
  fi
fi

Requites GNU grep(1)

edited May 2, 2021 at 20:39

answered May 2, 2021 at 17:36

Jetchisel

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8 Comments

Zang322 Over a year ago

thanks alot. I tried your code. it returns the following error test.sh: line 9: ed: command not found. Yes the change must be saved in the file

Jetchisel Over a year ago

Well, ed is not installed so use sed with the -i flag/option to edit the file.

Zang322 Over a year ago

when applying sed with flag -i, it write # correctly however, in the question it is meant that if user enters part1, then the # must be removed in part one (in case its outcommented) and thus becomes active code and part2 should be commented with # and thus becomes inactive and vice versa

Jetchisel Over a year ago

I have posted a new solution, try it out, I did no add the -i flag though.

Zang322 Over a year ago

perfect. you're really a gold mine. Thanks alot

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